Method of filling liquid into function liquid droplet ejection head, and ejection apparatus; method of manufacturing LCD device, organic EL device, electron emission device, PDP device, electrophoretic display device, color filter, and organic EL; and method of forming spacer, metallic wiring, lens, resist, and light diffusion member

ABSTRACT

An ejection apparatus has a carriage which moves relative to a workpiece. A function liquid droplet ejection head is held by the carriage and is provided with an ejection nozzle formed in a nozzle forming surface of a head main body. A liquid supply tank is connected to the ejection head. A cap unit is disposed in a position away from the workpiece and is provided, in a position corresponding to the function liquid droplet ejection head, with a cap which is connected to the suction pump and which is brought into intimate contact with the nozzle forming surface of the function liquid droplet ejection head so that the liquid of the liquid supply tank is filled into a flow passage inside the ejection head by a suction force to be operated upon through the cap. A gate valve is interposed in the liquid supply passage between the ejection head and the liquid supply tank. The gate valve is temporarily closed in the course of filling the liquid into the flow passage inside the ejection head, while maintaining suction by the cap.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a method of filling a liquid into a flowpassage inside a function liquid droplet ejection head, in which aliquid is filled into the flow passage inside the function liquiddroplet ejection head as represented by an ink jet head. It also relatesto an ejection apparatus using a function liquid droplet ejectionapparatus which is capable of being filled with the liquid in theabove-described method; and to a method of manufacturing a liquidcrystal display (LCD) device, a method of manufacturing an organicelectroluminescence (EL) device, a method of manufacturing an electronemission device, a method of manufacturing a plasma display panel (PDP)device, a method of manufacturing an electrophoretic display device, anda method of manufacturing a color filter, a method of manufacturing anorganic EL; as well as to a method of forming a spacer, a method offorming a metallic wiring, a method of forming a lens, a method offorming a resist, and a method of forming a light diffusion body.

2. Description of Related Art

An ink jet head of an ink jet printer (a liquid droplet ejection head)is capable of ejecting very minute ink droplets (liquid droplets) in theform of dots at a high accuracy. Therefore, it is expected to apply theliquid droplet ejection head to the field of manufacturing various kindsof parts by using, as the liquid to be ejected, function liquids such asspecial inks, photosensitive resins, or the like.

For example, it is considered to carry out the following operations.Namely, an ejection apparatus equipped with a main carriage which movesrelative to the workpiece such as a substrate of a color filter, or thelike, is used. A head unit having mounted a plurality of function liquiddroplet ejection heads on a subsidiary carriage which is detachably heldby a main carriage of the ejection apparatus, is carried into theejection apparatus. By the movement of the main carriage in this state,the head unit is relatively moved against the workpiece to thereby ejectthe liquid droplet from each of the ejection nozzles formed in a nozzleforming surface of each of the function liquid droplet ejection heads.The liquid crystal display device, organic EL display device, or thelike, is thus manufactured.

This kind of ejection apparatus has the following arrangement. Namely, aliquid is supplied from a common tank to each of the function liquiddroplet ejection heads by a slight (or small) head pressure so that theliquid droplet can be ejected at a higher accuracy by the operation of apump part which is assembled into the liquid droplet ejection head. In aposition which is away from the workpiece of the ejection apparatus,there is disposed a cap unit on which a plurality of caps to beconnected to a suction pump are mounted so as to correspond to theplurality of function liquid droplet ejection heads of the head unit.When a new head unit has been carried into the ejection apparatus, eachof the caps is brought into intimate contact with the nozzle formingsurface of each of the function liquid droplet ejection heads in a statein which the head unit has been moved to a position facing the cap unit.The liquid inside the liquid supply tank is filled into the flow passageinside each of the function liquid droplet ejection heads by means ofthe suction force to be operated upon through each of the caps.

As described above, even if the suction is carried out by the caps, theflow speed of the liquid inside the flow passage inside the functionliquid droplet ejection head lowers or drops. As a result, the airbubbles cannot be successfully removed out of the flow passage insidethe function liquid droplet ejection head, thereby causing the poorejection or failure in ejection of the liquid droplet under theinfluence of the remaining air bubbles. As a consequence, it becomesnecessary to repeat the suction operations several times, resulting inthe amount of liquid to be consumed at the time of filling, therebycausing a higher running cost.

In view of the above points, this invention provides a method of fillinga liquid into a flow passage inside a function liquid droplet ejectionhead, in which air bubbles can be efficiently removed out of the flowpassage inside the function liquid droplet ejection head. It alsoprovides an ejection apparatus which is suitable for carrying out theabove-described method, and a method of manufacturing an LCD device, amethod of manufacturing an organic EL device, a method of manufacturingan electron emission device, a method of manufacturing a PDP device, amethod of manufacturing an electrophoretic display device, a method ofmanufacturing a color filter, a method of manufacturing an organic EL,as well as a method of forming a spacer, a method of forming a metallicwiring, a method of forming a lens, a method of forming a resist, and amethod of forming a light diffusion body.

SUMMARY OF THE INVENTION

According to one aspect of this invention, there is provided a method offilling a liquid into a flow passage inside a function liquid dropletejection head having an ejection nozzle formed in a nozzle formingsurface of a head main body. The method comprises: bringing a capconnected to a suction pump into intimate contact with the nozzleforming surface; and filling a liquid of a liquid supply tank connectedto the function liquid ejection head into the flow passage inside thefunction liquid droplet ejection head. A liquid supply passage betweenthe function liquid droplet ejection head and the liquid supply tank istemporarily closed in a course of filling the liquid into the flowpassage inside the function liquid droplet ejection head whilemaintaining suction by the cap.

According to another aspect of this invention, there is provided anejection apparatus having: a carriage which moves relative to aworkpiece; a function liquid droplet ejection head which is held by thecarriage and which is provided with an ejection nozzle formed in anozzle forming surface of a head main body, the function liquid dropletejection head ejecting droplets from the ejection nozzle to theworkpiece while carrying out a relative movement between the carriageand the workpiece; a liquid supply tank which is connected to thefunction liquid droplet ejection head; a cap unit which is disposed in aposition away from the workpiece and which is provided, in a positioncorresponding to the function liquid droplet ejection head, with a capwhich is connected to a suction pump and is brought into intimatecontact with the nozzle forming surface of the function liquid dropletejection head, in a state in which the carriage is moved to a positionfacing the cap unit, so that the liquid of the liquid supply tank isfilled into a flow passage inside the function liquid droplet ejectionhead by a suction force to be operated upon through the cap. Theapparatus comprises: a gate valve interposed in the liquid supplypassage between the function liquid droplet ejection head and the liquidsupply tank, and the gate valve is temporarily closed in a course offilling the liquid into the flow passage inside the function liquiddroplet ejection head while maintaining suction by the cap.

According to the above-described arrangement, at the time of closing theliquid supply passage (at the time of closing the gate valve), the flowpassage inside the function droplet ejection head is reduced inpressure. As a result of subsequent opening of the liquid supply passage(at the time of opening the gate valve), the liquid suddenly flows andthe flow speed of the liquid in the flow passage inside the functionliquid droplet ejection head increases in speed, whereby the air bubblesinside the above-described flow passage are efficiently removed ordischarged. Therefore, the number of times of suction can be kept to aminimum, the amount of consumption of the liquid can be reduced, and theworking efficiency can be improved, resulting in the improvement in theworkability.

The higher the ratio of liquid filling into the flow passage inside thefunction liquid droplet ejection head before closing the liquid supplypassage, the higher the efficiency in the reduction of pressure in theflow passage inside function liquid droplet ejection head. Therefore,preferably, the closing of the liquid supply passage is carried intoeffect when the liquid inside the liquid supply tank has been sucked atleast up to the cap. In this case, preferably, the ejection apparatusfurther comprises a liquid sensor interposed in a suction passagebetween the cap and the suction pump, and the temporary closing of thegate valve is carried out when, after starting the liquid filling intothe flow passage inside the function liquid droplet ejection head, theliquid has been detected by the liquid sensor.

Preferably, the carriage further comprises a head unit which is made upof a sub-carriage and a plurality of function liquid droplet ejectionheads mounted on the sub-carriage, and the cap is provided in aplurality of numbers to correspond to the plurality of function liquiddroplet ejection heads. The gate valve is interposed in each of branchpassages of the liquid supply passage, each of the branch passages beingconnected by branching to each of the function liquid droplet ejectionheads. The liquid sensor is provided in each of the branch passages ofthe suction passages, each of the suction passages being connected toeach of the caps. Each of the gate valves is closed when the liquid isdetected by each of the liquid sensors.

According to this arrangement, even if the ratio of filling the liquidinto the function liquid droplet ejection heads varies from head tohead, the gate valve can be closed independently at an appropriatetiming for each of the function liquid droplet ejection heads, resultingin a large improvement in the productivity.

The shorter the length of the flow passage between the gate valve andthe function liquid droplet ejection head, the higher the efficiency ofreduction in pressure after the gate valve has been closed and thesmaller the amount of liquid consumption. Therefore, the gate valve ispreferably mounted on a portion which moves integrally with thecarriage. According to this arrangement, there is no need of securing,in a flow passage between the gate valve and the function liquid dropletejection head, a slack (or sag) for the purpose of following themovement of the head unit that is held on the carriage. This arrangementis advantageous in that the length of the flow passage can be shortened.

According to this invention, there is provided a method of manufacturingan LCD device in which a filter element is formed on a substrate of acolor filter by using the above-described ejection apparatus. The methodcomprises the steps of: introducing a filter material into the functionliquid droplet ejection head; carrying out a relative scanning betweenthe function liquid droplet ejection head and the substrate; andselectively ejecting the filter material to form the filter element.

According to this invention, there is provided a method of manufacturingan organic EL device in which an EL light emitting layer is formed on apixel on a substrate by using the above-described ejection apparatus.The method comprises the steps of: introducing a light emitting materialinto the function liquid droplet ejection head; carrying out a relativescanning between the function liquid droplet ejection head and thesubstrate; and selectively ejecting the light emitting material to formthe EL light emitting layer.

According to this invention, there is provided a method of manufacturingan electron emission device in which a fluorescent member is formed onan electrode by using the above-described ejection apparatus. The methodcomprises the steps of: introducing a fluorescent material into thefunction liquid droplet ejection head; carrying out a relative scanningbetween the function liquid droplet ejection head and the substrate; andselectively ejecting the fluorescent material to form the fluorescentmember.

According to this invention, there is provided a method of manufacturinga PDP device in which a fluorescent member is formed on a recessedportion on a back substrate by using the above-described ejectionapparatus. The method comprises the steps of: introducing a fluorescentmaterial into the function liquid droplet ejection head; carrying out arelative scanning between the function liquid droplet ejection head andthe substrate; and selectively ejecting the fluorescent material to formthe fluorescent member.

According to this invention, there is provided a method of manufacturingan electrophoretic display device in which an electrophoretic member isformed on a recessed portion on an electrode by using theabove-described ejection apparatus. The method comprises the steps of:introducing an electrophoretic material into the function liquid dropletejection head; carrying out a relative scanning between the functionliquid droplet ejection head and the substrate; and selectively ejectingthe electrophoretic material to form the electrophoretic member.

As described above, by using the above-described ejection apparatus inthe method of manufacturing an LCD device, the method of manufacturingan organic EL device, the method of manufacturing an electron emissiondevice, the method of manufacturing a PDP device, and the method ofmanufacturing an electrophoretic display device, the work of initialfilling (or charging) of the function liquid into the function liquiddroplet ejection head to be used in each of the above-described methodscan be carried out appropriately and smoothly. The scanning by theliquid droplet ejection head is generally main scanning and subsidiaryscanning (sub-scanning). In the case of an arrangement in which one lineis constituted by a single liquid droplet ejection head, there iscarried out only the sub-scanning. In addition, the above-describedelectron emission device is a generic term to include the idea of fieldemission display (FED) device.

According to this invention, there is provided a method of manufacturinga color filter in which a filter element is arrayed on a substrate byusing the above-described ejection apparatus. The method comprises thesteps of: introducing a filter material into the function liquid dropletejection head; carrying out a relative scanning between the functionliquid droplet ejection head and the substrate; and selectively ejectingthe filter material to form the filter element.

In this case, preferably, an overcoat layer is coated on the filterelement, and the method further comprises the steps of: introducing atranslucent coating material into the function liquid droplet ejectionhead after the filter element has been formed; carrying out a relativescanning between the function liquid droplet ejection head and thesubstrate; and selectively ejecting the coating material to form theovercoat layer.

According to this invention, there is provided a method of manufacturingan organic EL in which pixel inclusive of an EL light emitting layer isarrayed on a substrate by using the above-described ejection apparatus.The method comprises the steps of: introducing the light emittingmaterial into the function liquid droplet ejection head; carrying out arelative scanning between the function liquid droplet ejection head andthe substrate; and selectively ejecting the light emitting material toform the EL organic layer.

In this case, between the EL light emitting layer and the substrate,there is formed a pixel electrode corresponding to the EL light emittinglayer. The method preferably further comprises the steps of introducingthe liquid electrode material into the function liquid droplet ejectionhead; carrying out a relative scanning between the function liquiddroplet ejection head and the substrate; and selectively ejecting theliquid electrode material to form the pixel electrode.

In this case, there is formed an opposite electrode so as to cover theEL light emitting layer. The method preferably further comprises thesteps of: introducing the liquid electrode material into the functionliquid droplet ejection head; carrying out a relative scanning betweenthe function liquid droplet ejection head and the substrate; andselectively ejecting the liquid electrode material to form the oppositeelectrode.

According to this invention, there is provided a method of forming aspacer in which a particulate spacer is formed between two substrates soas to form a cell gap by using the above-described ejection apparatus.The method comprises the steps of: introducing a particulate materialinto the function liquid droplet ejection head; carrying out a relativescanning between the function liquid droplet ejection head and at leastone of the two substrates; and selectively ejecting the particulatematerial to form the opposite electrode.

According to this invention, there is provided a method of forming ametallic wiring in which a metallic wiring is formed on a substrate byusing the above-described ejection apparatus. The method comprises thesteps of: introducing a metallic wiring material into the functionliquid droplet ejection head; carrying out a relative scanning betweenthe function liquid droplet ejection head and the substrate; andselectively ejecting the metallic wiring material to form the metallicwiring.

According to this invention, there is provided a method of forming alens in which a microlens is formed on a substrate by using theabove-described ejection apparatus. The method comprises the steps of:introducing a lens material into the function liquid droplet ejectionhead; carrying out a relative scanning between the function liquiddroplet ejection head and the substrate; and selectively ejecting thelens material to form the microlens.

According to this invention, there is provided a method of forming aresist in which a resist of an arbitrary shape is formed on a substrateby using the above-described ejection apparatus. The method comprisesthe steps of: introducing a resist material into the function liquiddroplet ejection head; carrying out a relative scanning between thefunction liquid droplet ejection head and the substrate; and selectivelyejecting the resist material to form the resist.

According to this invention, there is provided a method of forming alight diffusion member in which a light diffusion member is formed on asubstrate by using the above-described ejection apparatus. The methodcomprises the steps of: introducing a light diffusion material into thefunction liquid droplet ejection head; carrying out a relative scanningbetween the function liquid droplet ejection head and the substrate; andselectively ejecting the light diffusion material to form the lightdiffusion member.

As described above, by using the above-described ejection apparatus inthe method of manufacturing a color filter, the method of manufacturingan organic EL, the method of manufacturing a metallic wiring, the methodof forming a lens, the method of forming a resist, and the method offorming a light diffusion member, the work of initial filling (orcharging) of the function liquid into the function liquid dropletejection head to be used in each of the above-described methods can becarried out appropriately and smoothly.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view showing the step of forming a bank portion(inorganic-matter bank) in manufacturing an organic EL device accordingto this invention;

FIG. 2 is a sectional view showing the step of forming a bank portion(organic-matter bank) in manufacturing the organic EL device accordingto this invention;

FIG. 3 is a sectional view showing the step of plasma processing(water-affinity processing) in manufacturing the organic EL deviceaccording to this invention;

FIG. 4 is a sectional view showing the step of plasma processing(water-repellency processing) in manufacturing the organic EL deviceaccording to this invention;

FIG. 5 is a sectional view showing the step of forming a hole injectionlayer (liquid droplet ejection) in the method of manufacturing theorganic EL device according to this invention;

FIG. 6 is a sectional view showing the step of forming the holeinjection layer (drying) in the method of manufacturing the organic ELdevice according to this invention;

FIG. 7 is a sectional view showing the step of surface modification(droplet ejection) in the method of manufacturing the organic EL deviceaccording to this invention;

FIG. 8 is a sectional view showing the step of surface modification(drying) in the method of manufacturing the organic EL device accordingto this invention;

FIG. 9 is a sectional view showing the step of blue color (B) lightemitting layer forming in the method of manufacturing the organic ELdevice according to this invention;

FIG. 10 is a sectional view showing the step of blue color (B) lightemitting layer forming (drying) in the method of manufacturing theorganic EL device according to this invention;

FIG. 11 is a sectional view showing the step of red color (R), greencolor (G), and blue color (B) light emitting layer forming in the methodof manufacturing the organic EL device according to this invention;

FIG. 12 is a sectional view showing the step of forming oppositeelectrodes in the method of manufacturing the organic EL deviceaccording to this invention;

FIG. 13 is a sectional view showing the step of sealing in the method ofmanufacturing the organic EL device according to this invention;

FIG. 14 is a schematic diagram of a hole injection layer formingapparatus according to this invention;

FIG. 15 is a schematic diagram of a light emitting layer formingapparatus according to this invention;

FIG. 16 is an outer perspective view of an imaging apparatus accordingto this invention;

FIG. 17 is a front view showing an outside of the imaging apparatusaccording to this invention;

FIG. 18 is a side view showing an outside of the imaging apparatusaccording to this invention;

FIG. 19 is a plan view showing an outside of the imaging apparatusaccording to this invention;

FIG. 20 is a schematic diagram showing a liquid droplet ejectionapparatus of the imaging apparatus according to this invention;

FIG. 21 is a plan view of a head unit according to this invention;

FIG. 22 is a side view of the head unit according to this invention;

FIG. 23 is a front view of the head unit according to this invention;

FIG. 24A is an outside perspective view of a piping joint and FIG. 24Bis a sectional view of the piping joint according to this invention;

FIG. 25A is an outside perspective view of a function liquid dropletejection head and FIG. 25B is a sectional view of the function liquiddroplet ejection head according to this invention;

FIG. 26 is a side view around a stone base of the ejection apparatusaccording to this invention;

FIG. 27 is a plan view around the stone base of the ejection apparatusaccording to this invention;

FIG. 28 is a front view around the stone base of the ejection apparatusaccording to this invention;

FIG. 29 is a schematic view showing the supporting mode of the stonebase of the ejection apparatus according to this invention;

FIG. 30 is a plan view of an X-axis table of the ejection apparatusaccording to this invention;

FIG. 31 is a side view of the X-axis table of the ejection apparatusaccording to this invention;

FIG. 32 is a front view of the X-axis table of the ejection apparatusaccording to this invention;

FIG. 33 is a perspective view around a main substrate recognition cameraof the ejection apparatus according to this invention;

FIG. 34 is a plan view of a Y-axis table of the ejection apparatusaccording to this invention;

FIG. 35 is a side view of the Y-axis table of the ejection apparatusaccording to this invention;

FIG. 36 is a front view of the Y-axis table of the ejection apparatusaccording to this invention;

FIG. 37 is a perspective view of a main carriage of the Y-axis tableaccording to this invention;

FIG. 38 is a plan view of the main carriage of the Y-axis tableaccording to this invention;

FIG. 39 is a perspective view of a common machine base of the ejectionapparatus according to this invention;

FIG. 40 is a perspective view of the common machine base of the ejectionapparatus according to this invention in a state in which the commonbase has been removed;

FIG. 41 is a side view of the common machine base of the ejectionapparatus according to this invention;

FIG. 42 is a plan view of the common machine base of the ejectionapparatus according to this invention;

FIG. 43 is a piping diagram of a function liquid supply and recoveryapparatus of the ejection apparatus according to this invention;

FIG. 44 is a perspective view around pumps of the liquid supply andrecovery apparatus according to this invention;

FIG. 45 is a plan view around the pumps of the liquid supply andrecovery apparatus according to this invention;

FIG. 46 is a perspective view around a waste liquid pump of the liquidsupply and recovery apparatus according to this invention;

FIG. 47 is a perspective view of a liquid supply tank of the liquidsupply and recovery apparatus according to this invention;

FIG. 48 is a side view of the liquid supply tank of the liquid supplyand recovery apparatus according to this invention;

FIG. 49 is a front view of the liquid supply tank of the liquid supplyand recovery apparatus according to this invention;

FIG. 50 is a perspective view of a rolling unit in a wiping unitaccording to this invention;

FIG. 51 is a plan view of the rolling unit in the wiping unit accordingto this invention;

FIG. 52 is a front view of the rolling unit in the wiping unit accordingto this invention;

FIG. 53 is a perspective view of a wipe-out unit in the wiping unitaccording to this invention;

FIG. 54 is a plan view of the wipe-out unit in the wiping unit accordingto this invention;

FIG. 55 is a front view of the wipe-out unit in the wiping unitaccording to this invention;

FIG. 56 is a schematic diagram showing the operation of the wiping unitaccording to this invention;

FIG. 57 is a outside perspective view of a cleaning unit according tothis invention;

FIG. 58 is a front view of the cleaning unit according to thisinvention;

FIG. 59 is a side view of the cleaning unit according to this invention;

FIG. 60 is a plan view of the cleaning unit according to this invention;

FIG. 61 is an enlarged sectional view of a cap of the cleaning unitaccording to this invention;

FIG. 62 is a perspective view of a flushing unit according to thisinvention;

FIG. 63 is a plan view of the flushing unit according to this invention;

FIG. 64 is a perspective view of a portion disposing gate valves inliquid supply passages according to this invention; and

FIG. 65 is a side view of the portion disposing the gate valves inliquid supply passages according to this invention

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

With reference to the accompanied drawings, a detailed description willnow be made about preferred embodiments of this invention. An ejectionapparatus of this embodiment is to be built into a manufacturing linefor manufacturing an organic EL device which is a kind of so-called flatdisplay device. By using a plurality of function liquid ejection heads,a function liquid such as light emitting material, or the like, isejected out of the ejection nozzles (ink jet method). There are thusformed an EL light emitting layer and hole injection layer which formthe light emitting function of the organic EL device

In this embodiment, a description will be made first about the structureof the organic EL device as well as about a method (or process) ofmanufacturing the organic EL device. Thereafter, a description will bemade about an apparatus for manufacturing an organic EL device which ismade up of an ejection apparatus for scanning a function dropletejection head which is mounted thereon, as well as about a method ofmanufacturing the organic EL device.

FIGS. 1 through 13 show the process of manufacturing an organic ELdevice inclusive of an organic EL element, and also show the structureof the organic EL device. This process is made up of the followingsteps: i.e., a step of forming a bank portion (also referred to as abank forming step); a step of plasma processing; a step of forming lightemitting element which in turn is made up of a step of forming a holeinjection/transport layer, and a step of forming a light emitting layer;a step of forming opposed (opposite or counter) electrodes; and a stepof sealing.

In the step of forming a bank portion, a bank layer 512 a made of aninorganic matter (hereinafter also called an inorganic-matter banklayer) and a bank layer 512 b made of an organic matter (also called anorganic-matter bank layer) are laminated in a predetermined position ona circuit element portion 502 and an electrode 511 (also called a pixelelectrode) which are formed in advance on a substrate 501. As described,the step of forming a bank portion includes a step of forming theinorganic-matter bank layer 512 a on a part of the electrode 511 as wellas a step of forming the organic-matter bank layer 512 b on theinorganic-matter bank layer 512 a.

First, in the step of forming the inorganic-matter bank layer 512 a, asshown in FIG. 1, a film of an inorganic matter such as SiO₂, TiO₂, orthe like, is formed on an interlayer dielectric 544 b of the circuitelement portion 502 and on the pixel electrode 511 of the circuitelement portion 502. This inorganic-matter bank layer 512 a is formedby, e.g., a chemical vapor deposition (CVD) method, a coating method, asputtering method, or the like, on an entire surface of the interlayerdielectric 544 b and on the pixel electrode 511.

Thereafter, this inorganic-matter film is subjected to patterning byetching, or the like, to thereby form a lower opening portion 512 cwhich corresponds to the position of forming an electrode surface 511 aof the electrode 511. At this time, it is necessary to form theinorganic-matter bank layer 512 a so as to overlap with the peripheralportion of the electrode 511. By thus forming the peripheral portion(only partly) of the electrode 511 in a manner to overlap with theinorganic-matter bank layer 512 a, the light emitting region of thelight emitting layer 510 (see FIGS. 10–13) can be controlled.

Then, in the step of forming the organic-matter bank layer 512 b, asshown in FIG. 2, an organic-matter bank layer 512 b is formed on theinorganic-matter bank layer 512 a. The organic-matter bank layer 512 bis etched by the art of photolithography, or the like, to thereby forman upper opening portion 512 d of the organic-matter bank layer 512 b.The upper opening portion 512 d is formed in a position whichcorresponds to the electrode surface 511 a and the lower opening portion512 c.

As shown in FIG. 2, the upper opening portion 512 d shall preferably beformed larger than the lower opening portion 512 c and smaller than theelectrode surface 511 a. According to this arrangement, the firstlaminated portion 512 e enclosing or surrounding the lower openingportion 512 c of the inorganic-matter bank layer 512 a is arranged toextend toward the center of the electrode 511 beyond the organic-matterbank layer 512 b. By thus bringing the upper opening portion 512 d andthe lower opening portion 512 c into communication with each other,there is formed an opening portion 512 g which passes or penetratesthrough the inorganic-matter bank layer 512 a and the organic-matterbank layer 512 b.

In the subsequent plasma processing step, there are formed a regionshowing an affinity with a liquid and a region showing a repellencyagainst the liquid on the surface of the bank portion 512 and on thesurface of the pixel electrode 511 a. This plasma processing step islargely classified into: a preliminary heating step; a step of causingto have an affinity with liquid (a liquid-affinity step) in which anupper surface 512 f of the bank portion 512, a wall surface of theopening portion 512 g, and an electrode surface 511 a of the pixelelectrode 511 are made to have liquid-affinity (property to show anaffinity with the liquid); a step of causing to have a repellencyagainst liquid (a liquid-repellency step) in which an upper surface 512f of the organic-matter bank layer 512 b and a wall surface of the upperopening portion 512 d are made to have liquid repellency (property toshow a repellency against the liquid); and a cooling step.

First, in the preliminary heating step, the substrate 501 inclusive ofthe bank portion 512 is heated to a predetermined temperature. Inheating the substrate 501, a heater is attached to a stage on which thesubstrate 501 is mounted and the substrate 501 is heated by this heatertogether with the stage. In concrete, it is preferable to make thepreliminary heating temperature to the range of, e.g., 70–80° C.

Then, in the liquid-affinity step, plasma processing (O₂ plasmaprocessing) is carried out in open air (outside air) with oxygen as aprocessing gas. As a result of this O₂ plasma processing,liquid-affinity processing is carried out, as shown in FIG. 3, on theelectrode surface 511 a of the pixel electrode 511, on the wall surfacesof the first laminated portion 512 e of the inorganic-matter bank layer512 a and of the upper opening portion 512 d of the organic-matter banklayer 512 b, and on the upper surface 512 f. As a result of thisliquid-affinity processing, hydroxyl group is introduced into each ofthese surfaces to thereby give them liquid-affinity properties. Thoseportions which are subjected to the liquid-affinity processing are shownby a chain line.

In the subsequent liquid-repellency processing step, plasma processingis carried out in the atmosphere of open air with methane tetrafluoride(CF₄) as the processing gas (CF₄ plasma processing). As a result of CF₄plasma processing, as shown in FIG. 4, the wall surface of the upperopening portion 512 d and the upper surface 512 f of the organic-matterbank layer are subjected to liquid-repellency processing. As a result ofthis liquid-repellency processing, fluorine group is introduced intoeach of the surfaces to thereby give them liquid-repellency properties.In FIG. 4, the regions showing the liquid-repellency properties areshown by a chain double-dashed line.

In the subsequent cooling step, the substrate 501 heated by the plasmaprocessing is cooled down to room temperature or to the controltemperature for the liquid droplet ejecting step. By thus cooling theplasma-processed substrate 501 down to the room temperature or to thepredetermined temperature (e.g., to the control temperature at which theliquid droplet ejection step is carried out), the subsequent holeinjection/transport layer forming step can be carried out at a giventemperature.

Then, in the light emitting element forming step, the holeinjection/transport layer and a light emitting layer are formed on thepixel electrode 511, thereby forming a light emitting element. The lightemitting element forming step is made up of the following four steps:i.e., a first liquid droplet ejection step in which a first compositionof matter for forming the hole injection/transport layer is ejected ontoeach of the pixel electrodes; a hole injection/transport layer formingstep in which the ejected first composition of matter is dried tothereby form the hole injection/transport layer on the pixel electrodes;a second liquid droplet ejection step in which a second composition ofmatter for forming the light emitting layer is ejected onto the holeinjection/transport layer; and a light emitting layer forming step inwhich the ejected second composition of matter is dried to thereby forma light emitting layer on the hole injection/transport layer.

First, in the first liquid droplet ejection step, the first compositionof matter inclusive of the material for forming the holeinjection/transport layer is ejected onto the electrode surface 511 a byink jet method (liquid droplet ejection method). This first liquiddroplet ejection step and the subsequent steps shall preferably becarried out in an atmosphere of an inert gas such as argon gas, or thelike, free from water and oxygen. In case the hole injection/transportlayer is formed only on the pixel electrodes, the holeinjection/transport layer to be formed adjacent to the organic-matterbank layer is not formed.

As shown in FIG. 5, the first composition of matter inclusive of thematerial for the hole injection/transport layer is filled into afunction liquid droplet ejection head H. An ejection nozzle of thefunction liquid droplet ejection head H is caused to face the pixelelectrode surface 511 a which is positioned inside the lower openingportion 512 c. While moving the function liquid droplet ejection head Hand the substrate 501 relative to each other, the first composition ofmatter 510 c whose amount of liquid per a droplet is kept under controlis ejected from the ejection nozzle toward the electrode surface 511 a.

As the first composition of matter to be used here, there may beemployed a composition formed by dissolving a mixture of a polythiophenederivative, such as poly(ethylenedioxy)tiophene (PEDOT), and poly(tyrenesulphonicacid) (PSS), or the like, in a polar solvent. As the polarsolvent, there may be mentioned glycol ethers, such as isopropyl alcohol(IPA), normal butanol, γ-utyrolactone, N-methyl-pyrrolidone (NMP), 1,3dimethyl-2-imidazolidinone (DMI) and derivatives thereof, carbitolacetate, and butylcarbitol acetate. It should be noted that as the holeinjection/transport layer-forming material, there may be used the samematerial for each of the light emitting layers 510 b of red color (R),green color (G), and blue color (B), and also there may be useddifferent materials for the respective light emitting layers.

As shown in FIG. 5, the ejected first composition of matter 510 spreadsor extends over the liquid-affinity processed electrode surface 511 aand over the first laminated portion 512 e and is filled into the lowerand upper opening portions 512 c, 512 d. The amount of the firstcomposition of matter to be ejected onto the electrode surface 511 a isdetermined by the size of the lower and upper opening portions 512 c,512 d, the thickness of the hole injection/transport layer, theconcentration of the material for forming the hole injection/transportlayer in the first composition of matter, or the like. The firstcomposition of matter 510 c may be ejected toward the same electrodesurface 511 a not only in one time but also in several times.

As shown in FIG. 6, in the hole injection/transport layer forming step,the ejected first composition of matter is subjected to the processingof drying and heat treatment. The polar solvent contained in the firstcomposition of matter is thus evaporated, and the holeinjection/transport layer 510 a is formed on the electrode surface 511a. By carrying out the drying processing, the evaporation of the polarsolvent contained in the first composition of matter 510 c occurs inportions which are close to the inorganic-matter bank layer 512 a andthe organic-matter bank layer 512 b and, consequently, not only is thepolar solvent evaporated but also is the hole injection/transport layerforming material condensed and deposited. As a result, the evaporationof the polar solvent occurs also on the electrode surface 511 a by thedrying processing. A flat portion 510 a which is made up of the holeinjection/transport layer forming material is thus formed on theelectrode surface 511 a. Since the speed of evaporation of the polarsolvent on the electrode surface 511 a is substantially uniform, thematerial to form the hole injection/transport layer 511 a is uniformlycondensed on the electrode surface 511 a, whereby the flat portion 510 aof a uniform thickness is formed.

In the subsequent second liquid droplet ejection step, the secondcomposition of matter containing the light emitting layer formingmaterial is ejected by the liquid droplet ejection method. In thissecond liquid droplet ejection step, non-polar solvent which isinsoluble to the hole injection/transport layer 510 a is used as asolvent for the second composition of matter which is used in formingthe light emitting layer, in order to prevent the holeinjection/transport layer 510 a from getting dissolved again.

On the other hand, since the hole injection/transport layer 510 a is lowin affinity to the non-polar solvent, the hole injection/transport layer510 a and the light emitting layer 510 b cannot be adhered to each otheror the light emitting layer 510 b cannot be uniformly coated even if thesecond composition of matter containing the non-polar solvent is ejectedonto the hole injection/transport layer 510 a. As a solution, in orderto enhance the surface affinity of the hole injection/transport layer510 a to the non-polar solvent and the light emitting layer formingmaterial, it is preferable to carry out the surface modification stepbefore forming the light emitting layer.

Therefore, a description will first be made about the surfacemodification step. The surface modification step is carried out bycoating the hole injection/transport layer 510 a with a solvent that isthe same as the non-polar solvent in the first composition of matter orwith a solvent which is similar thereto, by liquid droplet ejectionmethod, spin coating method, or dip coating method and, thereafter,drying it.

For example, the coating by the liquid droplet ejection method iscarried out in the following manner as shown in FIG. 7. Namely, thefunction liquid droplet ejection head H is filled with a surfacemodification solvent. The ejection nozzle of the function liquid dropletejection head H is caused to face the substrate (i.e., the substrate onwhich the hole injection/transport layer 510 a has been formed). Whilemoving the function liquid droplet ejection head H and the substrate 501relative to each other, the surface modification solvent 510 d isejected from the ejection nozzle H. Then, as shown in FIG. 8, thesurface modification solvent 510 d is dried.

Then, in the second liquid droplet ejection step, the second compositionof matter inclusive of the light emitting layer forming material isejected by the liquid droplet ejection method onto the holeinjection/transport layer 510 a. As shown in FIG. 9, the function liquiddroplet ejection head H is filled with the second composition of mattercontaining the blue color (B) light emitting layer forming material. Theejection nozzle of the function liquid droplet ejection head H is causedto face the hole injection/transport layer 510 a which is positionedinside the lower and upper opening portions 512 c, 512 d. While movingthe ink jet head H and the substrate 501 relative to each other, thesecond composition of matter 510 e whose amount of flow per each dropletis controlled is ejected from the ejection nozzle onto the holeinjection/transport layer 510 a

As the light emitting layer forming material, there may be usedpolyfluorene-based high polymer derivatives, (poly)paraphenylenevinylene derivatives, polyphenylene derivatives, polyvinylcarbazole,polythiophene derivatives, perylene-based dyes, coumarin-based dyes, andrhodamine-based dyes. Alternatively, it is possible to use one formed bydoping any of the above-described high polymers with an organic ELelement. For example, it is possible to use one doped with rubrene,peryene, 9,10-diophenylanthracene, tetraphenylbutadiene, Nile red,Coumarin-6, quinacridon, or the like.

As the non-polar solvent, solvents insoluble to the holeinjection/transport layer 510 a are preferable, and there may be used,e.g., cyclohexyl benzen, dihydrobenzofuran, trimethylbenzene,tetramethlbenzened, etc. By using such a non-polar solvent for thesecond composition of the light emitting layer 510 b, it is possible toapply the second composition without causing the holeinjection/transport layer 510 a to be dissolved again.

As shown in FIG. 9, the ejected second composition of matter 510 e isspread or extended over the hole injection/transport layer 510 a and isfilled into the lower and upper opening portions 512 c, 512 d. Thesecond composition of matter 510 e may be ejected onto the holeinjection/transport layer 510 a not only in one time but also in severaltimes. In this case, the quantity of the second composition of matter ineach time of ejection may be the same or may be changed from time totime.

Then, in the light emitting layer forming step, drying processing andheat treating processing are carried out after the second composition ofmatter has been ejected, whereby a light emitting layer 510 b is formedon the hole injection/transport layer 510 a. In the drying processing,the ejected second composition of matter is subjected to dryingprocessing to thereby evaporate the non-polar solvent contained in thesecond composition of matter. A blue color (B) light emitting layer 510b is thus formed as shown in FIG. 10.

Subsequently, as shown in FIG. 11, a red color (R) light emitting layer510 b is formed in the same way as in the case of the blue color (B)light emitting layer 510 b. Finally, a green color (G) light emittinglayer 510 b is formed. It is to be noted that the order of forming thelight emitting layers 510 b is not limited to the above-described order,but may be arbitrarily determined. For example, it is possible todetermine the order of forming the light emitting layers depending onthe light emitting layer forming materials.

Thereafter, in the opposed or opposite electrode forming step, a cathode503 (an opposed electrode) is formed on the entire surface of the lightemitting layer 510 b and the organic-matter bank layer 512 b as shown inFIG. 12. This cathode 503 may be formed by laminating a plurality ofmaterials. For example, on the side close to the light emitting layer,it is preferable to form a material with a small work function. Forexample, it is possible to use Ca, Ba, or the like. Depending on thematerial, on some cases, it is better to thinly form LiF, or the like,on a lower layer. It is further preferable to use on the upper side(sealing side) a material with a higher work function than that on thelower layer. These cathodes (cathode layers) 503 are preferably formedby vapor deposition method, sputtering method, chemical vapor deposition(CVD) method, or the like. Particularly, it is preferable to resort tothe vapor deposition method in order to prevent the light emitting layer510 b from being damaged by the heat.

Lithium fluoride may be formed only on the light emitting layers 510 b,and only on the blue color (B) light emitting layer 510 b. In this case,the other red color (R) light emitting layer and green color (G) lightemitting layer 510 b, 510 b will contact the upper cathode layer 503 bmade from LiF. In addition, on an upper portion of the cathode layer 12,it is preferable to use Al film, Ag film, or the like, which is formedby vapor deposition method, sputtering method, CVD method, or the like.Further, on top of the cathode 503, a protection layer such as of SiO₂,SiN, or the like, may be provided for the purpose of prevention ofoxidation.

In the sealing step as shown in FIG. 13, a sealing substrate 505 islaminated on top of the organic EL element 504 in the atmosphere of aninert gas such as of nitrogen, argon, helium, or the like. The sealingstep is preferably carried out in the atmosphere of the inert gas ofnitrogen, argon, helium, or the like. If the sealing step is carried outin the atmosphere of open air, there is a possibility of penetration ofwater, oxygen, or the like, into the defect portions if defects such asa pin hole, or the like, are present in the cathode 503. The cathode 503is thus oxidized, which is not preferable. Finally, the cathode 503 isconnected to the wiring of the flexible substrate and the wiring of thedriving IC circuit element portion 502 is connected, whereby the organicEL device 500 according to this embodiment is obtained.

A liquid material may be used also in the liquid-repellency film, thecathode 503, the pixel electrode 511, or the like, so that they can beformed by the liquid droplet ejection method.

Description will now be made about the apparatus for manufacturing anorganic EL device. As described hereinabove, in the process formanufacturing the organic EL device, the following steps are carried outby liquid droplet ejection method. Those steps in question are: the holeinjection/transport layer forming step (first liquid droplet ejectionstep+drying step) for forming the hole injection/transport layer (holeinjection layer); the surface modification step; and the light emittinglayer forming step (second liquid droplet ejection step+drying step) forforming the light emitting layer. Corresponding to the above steps, theapparatus for manufacturing the organic EL device according to thisembodiment employs an imaging apparatus (apparatus for making orplotting images or pictures) which carries out or performs scanningwhile ejecting light emitting function materials.

In concrete, as shown in FIG. 14, a hole injection layer formingapparatus A which carries out the hole injection/transport layer formingstep (inclusive of the surface modification step, if necessary) is madeup of: the above-described ejection apparatus 1 a which has mountedthereon function liquid ejection heads for introducing the first liquiddroplet (light emitting function material: hole injection layermaterial); a drying apparatus 2 a; a substrate transportation apparatus3 a; as well as a chamber apparatus 4 a which contains or houses thereinthe above apparatuses. As described above, it is preferable to carry outthe hole injection/transport layer forming step in the atmosphere of aninert gas. This chamber apparatus 4 a is used as a means for carryingout the step therein.

The chamber apparatus 4 a is made up of: a main chamber 4 aa whichcontains or houses therein the ejection apparatus 1 a; and a subsidiarychamber (sub-chamber) 4 ab which contains therein the drying apparatus 2a and the substrate transportation apparatus 3 a and which also containstherein in a tunnel shape the connecting portions (transportation paths)for connecting together the above-described chambers/apparatuses. Themain chamber 4 aa employs a system in which an appropriate or favorableatmosphere is generated therein by causing an inert gas to flowtherethrough continuously (details to be described hereinafter). Thesub-chamber 4 ab employs a system in which an appropriate or favorableatmosphere is generated therein by circulating an inert gastherethrough. In the figure, reference numeral 5 denotes a substratetransfer apparatus.

Similarly, as shown in FIG. 15, the light emitting layer formingapparatus B which carries out the light emitting layer forming step ismade up of: the above-described ejection apparatus 1 b having mountedthereon a function liquid droplet ejection head for introducing a secondliquid droplet (light emitting function materials: red (R) • green (G) •blue (B) light emitting layer materials); a drying apparatus 2 b; asubstrate transportation apparatus 3 b, the above-described apparatusesbeing provided in three sets, one for each of the above-describedcolors; as well as three sets of chamber apparatuses 4 b forrespectively containing therein the above-described apparatuses. In thesame manner as above, it is preferable to carry out the light emittinglayer forming step in the atmosphere of an inert gas. As a means forcarrying it out, there is provided the chamber apparatuses 4 b. Thesechamber apparatuses 4 b are also made up of: three main chambers 4 bafor containing therein respective ejection apparatuses 1 b, and threesub-chambers 4 bb for containing therein respective drying apparatuses 2b and respective substrate transportation apparatuses 3 b and forcontaining therein the respective connecting portions (transportationpaths) for connecting the above chambers/apparatuses.

It is to be noted that some parts or elements in the followingembodiments are provided in plural numbers instead of only one. In thefollowing detailed descriptions, they will sometimes be referred to in asingular form instead of in a plural form. It is partly for the sake ofsimplicity, or the like, and shall therefore be understood to includeplural form, too, where applicable and appropriate.

The ejection apparatus 1 a of the hole injection layer forming apparatusA and the ejection apparatus 1 b of the light emitting layer formingapparatus B are different from each other in the liquid material to beintroduced into the respective function liquid droplet ejection headsand have otherwise the same construction. In addition, the dryingapparatuses 2 a, 2 b, the substrate transportation apparatuses 3 a, 3 b,and the chamber apparatuses 4 a, 4 b have respectively the constructionthat is the same as, or similar to, each other. If the time required forthe exchanging of the function liquid ejection heads or the exchangingof the supply systems for the light emitting function materials is leftout of consideration, it is thus possible to manufacture an organic ELdevice in an arbitrary set of apparatuses (ejection apparatus 1, dryingapparatus 2, substrate transportation apparatus 3, and chamber apparatus4).

Therefore, in this embodiment, description is made hereinbelow about theconstruction of one set of apparatuses on the left end in FIG. 15, i.e.,the ejection apparatus 1 b for forming a light emitting layer of bluecolor (B), the drying apparatus 2 b, the substrate transportationapparatus 3 b, and the chamber apparatus 4 b, and the description aboutthe other apparatuses is omitted.

A substrate that has been processed in the above-described bank formingstep and the plasma processing step is transported from the substratetransfer apparatus 5 which is located at the left end in FIG. 15 to thesubstrate transportation apparatus 3 (3 b) by means of an apparatus (notillustrated), and is changed therein in its direction and posture forbeing further transported to the ejection apparatus 1 (1 b). Thesubstrate that has been handed over from the substrate transportationapparatus 3 (3 b) to the ejection apparatus 1 (1 b) is set in positionon the ejection apparatus 1 (1 b). In the ejection apparatus 1 (1 b) alight emitting material (liquid droplet) of blue color (B) is ejected bythe function liquid droplet ejection head to a multiplicity of pixelregions (opening portions 512 g) in the substrate (second liquid dropletejection step).

Then, the substrate to which the light emitting material has been coatedor adhered is handed over from the ejection apparatus 1 (1 b) to thesubstrate transportation apparatus 3 (3 b), and is introduced by thesubstrate transportation apparatus 3 (3 b) into the drying apparatus 2(2 b). In the drying apparatus 2 (2 b), the substrate is exposed to ahigh-temperature atmosphere of an inert gas for a predetermined periodof time to thereby evaporate the solvent in the light emitting material(drying step). Here, the substrate is again introduced into the ejectionapparatus 1 (1 b) to carry out the second liquid droplet ejection step.In other words, the second liquid droplet ejection step and the dryingstep are repeated for a plurality of times. Once the light emittinglayer has attained a desired thickness, the substrate is transportedthrough the substrate transportation apparatus 3 (3 b) to the centralejection apparatus 1 (1 b) so as to form a light emitting layer of redcolor (R), and is finally transported to the right end ejectionapparatus 1 (1 b) to form therein a light emitting layer of green color(G). These steps are carried out in the atmosphere of an inert gasinside the above-described chamber apparatus 4 (4 b). It is to be notedhere that the order of forming each of the blue, red and green colorlight emitting layers may be arbitrarily selected.

Detailed descriptions about the drying apparatus 2 and the substratetransportation apparatus 3 are omitted. It is, however, to be noted thatthe drying apparatus 2, for example, shall preferably employ a system ofusing a hot plate or a lamp (infrared lamp), aside from a blow dryingsystem in which an inert gas is blown, a vacuum drying system, or thelike. The drying temperature shall preferably be set to 40° C. through200° C.±2° C.

Detailed description will now be made about the ejection apparatus 1.The ejection apparatus 1 is made up, as shown in FIGS. 16 through 19, ofa liquid droplet ejection apparatus (liquid droplet ejection means) 10and an auxiliary apparatus 11. The auxiliary apparatus 11 is made up of:a liquid supply and recovery apparatus 13 which supplies the liquiddroplet ejection apparatus 10 with a liquid material and which alsorecovers the liquid that has become useless (that has been put out ofservice); an air supply apparatus 14 which supplies each of theconstituting parts with compressed air for use in driving/controlling,or the like; a vacuum suction apparatus 15 which sucks air; and amaintenance apparatus 16 which is used for maintenance of the functionliquid droplet ejection head 7; or the like.

The liquid droplet ejection apparatus 10 is made up of: a supportingrack 21 disposed on a floor; a stone base 22 disposed on the supportingrack 21; an X-axis table 23 disposed on the stone base 22 and a Y-axistable 24 which crosses the X-axis table 23 at a right angle; a maincarriage 25 disposed in a manner to be suspended from the Y-axis table24; and a head unit 26 mounted on the main carriage 25. The head unit 26has mounted thereon a plurality of function liquid droplet ejectionheads 7 (details are given hereinafter). To correspond to theseplurality of function liquid droplet ejection heads 7, a substrate(workpiece) W is set in position on a suction table 81 of the X-axistable 23.

The liquid droplet ejection apparatus 10 of this embodiment has aconstruction in which the substrate W is moved in a manner synchronizedwith the driving of the function liquid droplet ejection heads 7(selective ejection of the function liquid droplet). The so-called mainscanning of the function liquid droplet ejection heads 7 is carried outby the reciprocating (back and forth) movements of the X-axis table 23in the X-axis direction. The so-called subsidiary scanning(sub-scanning) in correspondence to the main scanning is carried out bythe reciprocating (back and forth) movements of the function liquiddroplet ejection heads 7 in the Y-axis direction by the Y-axis table 24.It is of course possible to carry out the main scanning only by theforward movement (or by the backward movement) in the X-axis direction.

On the other hand, the home position of the head unit 26 is defined tobe in the left end position as seen in FIGS. 17 and 19. From the leftside of this liquid droplet ejection head 10, the head unit 26 isbrought into or replaced (details will be given hereinafter). To thisside (i.e., to the side of the viewer) of the figure, theabove-described substrate transportation apparatus 3 faces, and thesubstrate W is carried into, or brought out from, this side of thefigure. To the right side, as seen in the figure, of the liquid dropletejection apparatus 10, there are integrally disposed main constitutingapparatuses of the above-described auxiliary apparatus 11.

The auxiliary apparatus 11 is made up of: a common machine base 31 of acabinet style; the air supply apparatus 14 and the vacuum suctionapparatus 15 which are contained or housed inside one half of the commonmachine base 31; the above-described function liquid supply and recoveryapparatus 13 which is contained in the other one half of the commonmachine base 31; and the above-described maintenance apparatus 16 whichcontains the main constituting apparatuses on the common machine base31.

The maintenance apparatus 16 is made up of: a flushing unit 33 in whichthe function liquid droplet ejection heads 7 are subjected to regularflushing operation (ejection work to discard the function liquid fromall of the ejection nozzles); a cleaning unit 34 which carries out thesuction and keeping of the function liquid from the function liquiddroplet ejection heads 7; and a wiping unit 35 which wipes out thenozzle forming surfaces of the function liquid droplet ejection heads 7.The cleaning unit 34 and the wiping unit 35 are disposed on the commonmachine base 31.

The main chamber 4 is made in the form of a so-called clean room, asshown in FIGS. 14 and 15, which has disposed in a chamber room 37 anelectrical room 38 and a mechanical room (or machine room) 39 in a sideby side relationship. The chamber room 37 is filled with nitrogen gaswhich is an inert gas. The above-described liquid droplet ejectionapparatus 10 and the auxiliary apparatus 11 are exposed to theatmosphere of nitrogen gas as a whole and are operated in the atmosphereof nitrogen gas.

Here, with reference to a schematic diagram in FIG. 20, a briefdescription will be made about the series of operations of the ejectionapparatus 1 which operates in the atmosphere of nitrogen gas. First, asa preparatory step, the head unit 26 is brought into the liquid dropletejection apparatus 10 and is set in position on the main carriage 25.Once the head unit 26 has been set in position on the main carriage 25,the Y-axis table 24 moves the head unit 26 to a position of a headrecognition camera (not illustrated) to thereby recognize the positionof the head unit 26 by means of a head recognition camera. Based on theresult of this recognition, the head unit 26 is corrected in respect ofa Θ axis, and the head unit 26 is subjected to a positional correctionin respect of the X-axis direction and the Y-axis direction in terms ofdata. After the positional correction, the head unit 26 (main carriage25) returns to the home position.

On the other hand, once the substrate W (in this case, each of thesubstrates to be introduced) is introduced into the suction table 81 ofthe X-axis table 23, a main substrate recognition camera 90 (to bedescribed in detail hereinafter) recognizes the position of thesubstrate at that position (the position of handing over and receiving).Based on the result of this recognition, the substrate W is corrected inrespect of the Θ axis, and a positional correction of the substrate W inrespect of the X-axis direction and the Y-axis direction is carried outin terms of the data. After the positional correction, the substrate W(suction table 81) returns to the home position. At the time of aninitial adjustment of the X-axis table 23 and the Y-axis table 24(so-called center alignment), an alignment mask is introduced onto thesuction table 81 to thereby carry out the initial adjustment by means ofa subsidiary substrate recognition camera 108 which is described indetail hereinafter.

Once the preparations have been finished as described above, in theactual liquid droplet ejection operation, the X-axis table 23 is firstdriven to thereby move the substrate W back and forth in the mainscanning direction. The plurality of function liquid droplet ejectionheads 7 are also driven to thereby carry out the selective ejectionoperation of the function liquid droplets toward the substrate W. Afterthe substrate W has returned, the Y-axis table 24 is then driven tothereby move the head unit 26 by one pitch in the subsidiary scanningdirection. The back and forth movements of the substrate W and thedriving of the function liquid droplet ejection heads are carried outagain. By repeating these operations several times, the liquid dropletscan be ejected from end to end over the entire region of the substrateW.

In this embodiment, the substrate W which is the object to which thefunction liquid droplet ejection is made is moved in the main scanningdirection (X-axis direction) relative to the head unit 26. It may alsobe arranged that the head unit 26 is moved in the main scanningdirection. Or else, there may be employed an arrangement in which thehead unit 26 is fixed or stationary and in which the substrate W ismoved in the main scanning direction and in the sub-scanning direction.

Then, a description will now be made about the arrangement of the liquiddroplet ejection apparatus 10 and the auxiliary apparatus 11. Beforeproceeding further, in order to facilitate the understanding, a detaileddescription will be made about the head unit 26 which constitutes themain portion of the liquid droplet ejection apparatus 10.

FIGS. 21 through 24 are arrangement drawings of the head unit. As showntherein, the head unit 26 is made up of: a subsidiary carriage(sub-carriage) 41; a plurality of (twelve) function liquid dropletejection heads 7 which are mounted on the sub-carriage 41; and aplurality of (twelve) head holding members 42 for mounting each of thefunction liquid droplet ejection heads 7 on the sub-carriage 41. Twelvefunction liquid droplet ejection heads 7 are divided into right and leftgroups of six each and are disposed at a predetermined angle to the mainscanning direction.

The six function liquid droplet ejection heads 7 of one group aredisposed at a positional deviation, in the sub-scanning direction,relative to the six function liquid droplet ejection heads 7 of theother group. In this manner, all of the ejection nozzles 68 (to bedescribed in detail hereinafter) of the twelve function liquid dropletejection heads 7 are continuous (partly overlapped) in the sub-scanningdirection. In other words, the head arrangement in this embodiment issuch that, on the sub-carriage 41, six function liquid droplet ejectionheads 7 disposed at an angle in the same direction are provided in tworows and that the function liquid droplet ejection heads 7 in one of thehead rows are disposed at 180° rotation relative to the other of thehead rows of the function liquid droplet ejection heads 7.

The above-described arrangement pattern is only one example. Theadjoining function liquid droplet ejection heads 7 within one head rowmay be disposed at an angle of 90° relative to each other, or else thefunction liquid droplet ejection heads 7 of one head row may be disposedat an angle of 90° relative to the function liquid droplet ejectionheads of the other head row. Anyway, as long as the dots by all of theejection heads 68 of the twelve function liquid droplet ejection heads 7are continuous in the sub-scanning direction, they serve the purpose.

In addition, if the function liquid droplet ejection heads 7 are made tobe parts for exclusive use by each kind of substrate W, it is notnecessary to take the trouble of setting the function liquid dropletejection heads 7 at an inclination. Instead, it is sufficient to arrangethem in a staggered or stepped manner. In more detail, as long as anozzle array (dot array) of a predetermined length can be constituted,they may be constituted by a single function liquid droplet ejectionhead 7 or by a plurality of function liquid droplet ejection heads 7. Itfollows that the number of the function liquid droplet ejection heads 7and the number of the rows, as well as the arrangement pattern may bearbitrarily selected.

The sub-carriage 41 is made up of: a main body plate 44 which issubstantially square in shape and partly notched; a pair of left andright standard or reference pins 45, 45 which are provided in anintermediate position as seen in the long side of the main body plate44; a pair of left and right supporting members 46, 46 which areattached to both the long sides of the main body plate 44; and a pair ofleft and right handles 47, 47 which are provided at an end of each ofthe supporting members 46. The left and right handles 47, 47 serve asmembers for holding the head unit 26 when an assembled head unit 26, forexample, is mounted onto the above-described liquid droplet ejectionapparatus 10. The left and right supporting members 46, 46 serve asmembers for fixing the sub-carriage 41 to the setting portion of theliquid droplet ejection apparatus 10 (details thereof will be describedhereinafter). Further, the pair of the standard pins 45, 45 serve as thestandard for positioning (positionally recognizing) the sub-carriage(head unit 26), based on the image recognition, in the X-axis, Y-axis,and the Θ-axis directions.

The sub-carriage 41 is further provided with a piping joint 49 at aposition away from each of the function liquid droplet ejection heads,e.g., at an end portion on the side of the handle 47 of the sub-carriage41. The piping joint 49 serves the purpose of detachably connecting:that piping material 48 a on the side of the head (head-side pipingmaterial 48 a) which is communicated with each of the function liquiddroplet ejection heads through a piping adapter 48; and that pipingmaterial on the side of the apparatus (apparatus-side piping material)which is communicated with a liquid supply tank 126 (to be describedhereinafter) for the liquid supply and recovery apparatus 13.

As shown in FIGS. 24A and 24B, the piping joint 49 is provided with anoblong plate 491 which is fixed to an end on the side of the handle 47in the sub-carriage 41 through a bracket 490. Twelve sockets 492 intotal in the upper and lower rows are fixed by fitting to the plate 491.One end of each of the sockets 492 has connected thereto each of thehead-side piping material 48 a through a piping coupling 493. The otherend of each of the sockets 492 has formed therein a plug hole 492 a intowhich a plug 494 is detachably fitted (i.e., fitted in a manner capableof being plugged into and plugged out of position).

The apparatus-side piping material is connected to the plugs 494 throughelbow pipes 495. In this manner, by simply plugging each of the plugs494 into, and out of, each of the sockets 492, the apparatus-side pipingmaterial can be connected to, or detached from, the head-side pipingmaterial 48 a. Even if there occurs a liquid run (running or flowing ordripping of the liquid) at the time of separating the piping material,there is no possibility of the running liquid's getting adhered to theconnectors 66 (see FIG. 25A) of the function liquid droplet ejectionheads 7 because the piping joint 49 is away from the function liquiddroplet ejection heads 7. The plugs 494 are prevented from beinginadvertently pulled out of position due to a stay bar 497 which isdetachably mounted on the plate 491 through screws 496 on both endsthereof.

In case there occurs a clearance (or gap) to the plug 494 within theplug hole 492 a, the air bubbles through the clearance penetrate intothe function liquid droplet ejection heads 7, resulting in a failure inejection (or wrong ejection) of the liquid droplet. As a solution, inthis embodiment, the hole bottom surface 492 b of the plug hole 492 a isformed into a tapered surface to suit the taper of the front end of theplug 494 to thereby prevent the clearance from occurring. A clearancemay occur to a smaller degree between the hole bottom surface 492 b andthe front end of the plug 494 through a dimensional tolerance in thedepth of the plug hole 492 a and the length of the plug 494. However,since this clearance is directed in a tapered shape in the direction offlow of the liquid that flows out of the plug 494, the air bubbles canbe easily removed by suction out of the clearance at the step of liquidfilling which is carried out when the head unit 26 is placed in positionin the ejection apparatus 1. Therefore, there is no possibility of theair bubbles' getting into the function liquid droplet ejection heads 7through the clearance during operation of the ejection apparatus 1.

In this embodiment, a plurality of, e.g., two O-rings 498 for thepurpose of sealing the plug holes 492 a are attached to the perimeter ofthe plug 494 at an axial distance from each other. The sealing propertybetween the plug 494 and the socket 492 is thus improved.

Though not illustrated, the sub-carriage 41 is provided, on an upperside of the two rows of the left and right function liquid dropletejection head groups, with a pair of left and right wiring (or cable)connection assemblies to be connected to the function liquid dropletejection heads 7. Each of the wiring connection assemblies is arrangedto be connected by wires (or cables) to the a control apparatus (headdriving unit, not illustrated) of the ejection apparatus 1.

As shown in FIGS. 25A and 25B, the function liquid droplet ejection head7 is of a so-called dual (twin) construction and is made up of: a liquidintroduction part 61 having dual connection needles 62, 62; a dual headsubstrate 63 which is in communication with a side of the liquidintroduction part 61; a dual pump part 64 which is in communication witha lower portion of the liquid introduction part 61; and a nozzle formingplate 65 which is in communication with the pump part 64. Each of theconnection needles 62 has connected thereto the above-described pipingadapter 48. To the base portion of each of the connection needles 62there is mounted a filter 62 a for preventing foreign substances fromgetting into the pump part 64. Flexible flat cables (not illustrated) tobe drawn (or pulled out) from the wiring connection assemblies areconnected to the connectors 66, 66 of the head substrate 63.

A rectangular head main body 60 which projects toward the back side ofthe sub-carriage 41 is constituted by the pump part 64 and the nozzleforming plate 65. A nozzle forming surface 67 of the nozzle formingplate 65 has parallelly disposed therein two rows of nozzle arrays 69,69, each row having a multiplicity of ejection nozzles 68. The pipingadapters 48 are arranged such that two of them are respectively disposedfor each of the function liquid droplet discharge heads 7 incorrespondence to the dual connection needles 62, 62. Therefore, thehead-side piping material 48 a to be connected to each of the sockets492 of the piping joint 49 is connected to the two piping adapters 48,48 through a Y-shaped coupling 49.

A description will now be made in sequence about the other constitutingapparatuses of the liquid droplet ejection apparatus 10 and theauxiliary apparatus 11.

FIGS. 26 through 29 show the supporting rack 21 and the stone base 22 onwhich is mounted the X-axis table. As shown in these figures, thesupporting rack 21 is constituted by assembling L-shaped structuralmembers, or the like, into a rectangle, and has a plurality of (nine)supporting legs 71 with adjusting bolts which are distributed in a lowerpart thereof. On an upper part of the supporting rack 21 there areprovided, in a manner extending sidewise and two in number for eachside, a plurality of (eight) fixing members 72 for fixing the stone base22 at the time of movement such as transportation, or the like. Each ofthe fixing members 72 is formed into an L shape like a bracket and isfixed, at its base end, to the upper side face of the supporting rack 21and is brought, at its front end, into contact with the lower side faceof the stone base 22 through the adjusting bolts 73. The stone base 22is placed in position on the supporting rack 21 in an untied state. Whenthe stone base 22 is transported, it is fixed by the fixing members 72to the supporting rack 21 in a manner immovable in the X-axis directionand in the Y-axis direction (i.e., back-and-forth and sidewisedirections) relative to the supporting rack 21.

The stone base 22 is to support the X-axis table 23 and the Y-axis table24, both being for moving the function liquid droplet ejection heads 7at a high accuracy, so as not to give rise to deviations in accuracy(especially in respect of the degree of flatness) due to environmentalconditions, vibrations, or the like. It is constituted by a solid stonematerial which is rectangular in plan view. The stone base 22 isprovided at its lower part with three main supporting legs 75 and sixauxiliary legs 76, all with adjusting bolts, for supporting the stonebase 22 on the supporting rack 21. The three main supporting legs 75support the stone base 22 at three points to thereby secure the degreeof parallelism of the surface (also to secure the degree ofhorizontalness). The six auxiliary legs 76 are to support the portionsaway from the three main supporting legs 75 of the stone base 22 tothereby keep the stone base 22 from deflecting.

For this purpose, as schematically shown in FIG. 29, the three mainsupporting legs 75, 75, 75 are disposed in a manner to form an isoscelestriangle with the two main legs 75 forming the base being positioned onthat side of the stone base 22 from which the substrate is transported(i.e., on the left side in FIG. 29 and on this side, i.e., on the sideof the viewer of the figure, in FIG. 16). The six auxiliary legs 76, 76,76, 76, 76, 76 are evenly distributed in such a manner that theyconstitute 3×3 in the longitudinal and lateral directions inclusive ofthe above-described three main supporting legs 75, 75, 75.

In this arrangement, the X-axis table 23 is disposed such that the axialline thereof coincides with the center line along the long sides of thestone base 22, and the Y-axis table 24 is disposed such that the axialline thereof coincides with the center line along the short sides of thestone base 22. Therefore, the X-axis table 23 is fixed directly to thestone base 22 and the Y-axis table 24 is fixed to the stone base 22 byfour supporting columns 78 through respective spacer blocks 79. As aresult, the Y-axis table 24 is disposed so as to lie above the X-axistable 23 at right angles thereto. Reference numeral 80 in FIG. 27denotes four small blocks for fixing thereto main substrate recognitioncameras which are described in detail hereinafter. The main substraterecognition cameras are also fixed to the stone base 22.

As shown in the X-axis moving system in FIGS. 26 through 28 and in theΘ-axis moving system in FIGS. 30 through 32, the X-axis table 23 extendsalong the long sides of the stone base 22 and is made up of: a suctiontable 81 which sucks the substrate W in position by air suction; aΘ-axis table 82 which supports the suction table 81 (see FIGS. 30through 32); an X-axis air slider 83 which supports the Θ-axis table 82in a manner slidable in the X-axis direction; an X-axis linear motor 84which moves the substrate W on the suction table 81 in the X-axisdirection through the Θ-axis table 82; and an X-axis linear scale 85which is provided in line with the X-axis air slider 83 (see FIGS. 26through 29).

The X-axis linear motor 84 is positioned on that side of the X-axis airslider 83 from which the head unit 26 is transported, and the X-axislinear scale 85 is positioned on that side of the X-axis air slider 83on which the auxiliary apparatus 11 is disposed, and the X-axis airslider 83 and the X-axis linear scale 85 are disposed in parallel witheach other. The X-axis linear motor 84, the X-axis air slider 83 and theX-axis linear scale 85 are directly supported on the stone base 22. Thesuction table 81 has connected thereto a vacuum pipe (not illustrated)which is in communication with the above-described vacuum suctionapparatus 15. The substrate W which is set in position by the airsuction is held by suction in order to maintain its flatness.

The X-axis linear scale 85 has, on the side of the auxiliary apparatus11, an X-axis flexible cable bundler 87 in parallel with the linearscale 84 in a state in which it is contained in a box 88 on the stonebase 22. The X-axis flexible cable bundler 87 contains therein vacuumpipes for the suction table 81, cables for the Θ-axis table 82, or thelike, so that they follow the movement of the suction table 81 and theΘ-axis table 82 (see FIGS. 27 and 28).

The X-axis table 23 constituted as described above is operated by thedriving of the X-axis linear motor 84 such that the suction table 81having sucked thereto the substrate W and the Θ-axis table 82 are movedin the X-axis direction guided by the X-axis air slider 83. In thereciprocating movements in the X-axis direction, the relative mainscanning of the function liquid droplet ejection heads 7 is carried outby the forward movement from the side of transportation of the substratetoward the inner side. In addition, based on the result of recognitionby the main substrate recognition camera 90 (to be described in detailhereinafter), the Θ-axis correction (angular correction within thehorizontal plane) of the substrate W is carried out by the Θ-axis table82.

FIG. 33 shows the main substrate recognition camera. As shown therein,there are disposed a pair of main substrate recognition cameras 90, 90right above the suction table 81 so as to face the position in which thesubstrate is transported (receiving and handover position). The pair ofmain substrate recognition cameras 90, 90 are arranged to simultaneouslycarry out the image-wise recognition (recognition by means of an image)of the two reference positions of the substrate.

As shown in FIGS. 34, 35 and 36, the Y-axis table 24 extends along theshort sides of the stone base 22 and is made up of: a bridge plate 91which suspends the main carriage 25; a pair of Y-axis sliders 92, 92which support the bridge plate 91 on both ends so as to be slidable inthe Y-axis direction; a Y-axis linear scale 93 which is provided inparallel with the Y-axis slider 92; a Y-axis ball screw 94 which movesthe bridge plate 92 in the Y-axis direction guided by the pair of Y-axissliders 92, 92; and a Y-axis motor 95 which rotates the Y-axis ballscrew in one direction and in the opposite direction of rotation. A pairof Y-axis flexible cable bundlers 96, 96 are disposed in a mannerrespectively housed in boxes 97, 97.

The Y-axis motor 95 is constituted by a servo motor. When the Y-axismotor 95 rotates in one direction and in the opposite direction ofrotation, the bridge plate 91 which is in screwed engagement therewiththrough the Y-axis ball screw 94 moves in the Y-axis direction with thepair of the Y-axis sliders 92, 92 serving as the guides. In other words,accompanied by the movement of the bridge plate 91 in the Y-axisdirection, the main carriage 25 moves in the Y-axis direction. In theback and forth movements of the main carriage 25 (head unit 26) in theY-axis direction, the sub-scanning by the function liquid dropletejection heads 7 is carried out in the forward movement from the homeposition toward the auxiliary apparatus 11.

On the four supporting columns 78 there are supported thereon amounting-base plate 98 with the moving path portion of the main carriage25 forming a rectangular opening 98 a. On the mounting-base plate 98there are disposed the pair of Y-axis sliders 92, 92 to stand clear ofthe rectangular opening 98 a, and the Y-axis ball screw 94 in parallelwith each other. On a pair of supporting plates 99, 99 which extendoutward from the mounting-base plate 98, there are placed theabove-described pair of Y-axis flexible cable bundlers 96, 96 togetherwith the boxes 97, 97 therefor.

The Y-axis flexible cable bundler 96 on the side of transporting thesubstrate houses therein the cables which are mainly connected to thehead unit 26. The Y-axis flexible cable bundler on the opposite sidehouses therein those pipes for the function liquid droplet which aremainly connected to the head unit 26 (both not illustrated). Thesecables and pipes are connected to the plurality of function liquiddroplet ejection heads 7 in the head unit 26 through the bridge plate91.

As shown in FIGS. 37 and 38, the main carriage 25 is made up of: asuspending member 101 which is fixed to the bridge plate 91 from thebottom side and which is of I-shape in external appearance; a Θ-axistable 102 which is attached to the lower surface of the suspendingmember 101; and a carriage main body 103 which is attached to the lowersurface of the Θ-axis table 102 in a suspended manner. This suspendingmember 101 faces the rectangular opening 98 a of the mounting-base plate98.

The carriage main body 103 is made up of: a base plate 104 on which thehead unit 26 is seated; an arch (portal) member 105 which supports thebase plate 104 in a suspended manner; a pair of provisional placingL-shaped (angular) members 106, 106 which are provided so as to protrudefrom one end of the base plate 104; and a stopper plate 107 which isprovided at the other end of the base plate 104. On an outside of thestopper plate 107 there are disposed a pair of the above-describedsubsidiary substrate recognition cameras 108 which recognize thesubstrate W.

The base plate 104 has formed therein a rectangular opening 111 intowhich the main body plate 44 of the head unit 26 is loosely fitted. Eachleft and right opening edge portion 112 of the base plate 104, whichforms the rectangular opening 111, is provided with bolt holes 113, 113,two penetrating holes 114, 114, and positioning pins 115 which are usedfor positioning and fixing the head unit 26.

Into the main carriage 25 which is constituted as described above, thehead unit 26 is transported and set in position by holding it with boththe handles 47, 47. Namely, the transported head unit 26 is once placedon both the provisional placing L-shaped members 106, 106 (provisionalplacing). Then, the pipes which are in communication with the functionalliquid supply and recovery apparatus 13 which is disposed on the bridgeplate 91 are connected to the pipe connection assembly 49 of the headunit 26, and is also the cables of the control system are connected tothe cable connection assembly 50. Then, by holding both the handles 47,47 again, the head unit 26 is pushed forward with both the provisionalplacing L-shaped members 106, 106 serving as guides. The head unit 26 isthus set in position into the left and right opening edges 112, 112 ofthe base plate 104.

A description will now be made about the common machine base 31. Asshown in FIGS. 39 through 42, the common machine base 31 is made up of:a machine base main body 121 in which two containing rooms, i.e., alarge containing room 122 a and a small containing room 122 b, areformed with a partition wall therebetween; a movable table 123 which isprovided on the machine base main body 121; a common base 124 which isfixed to the movable table 123; and a tank base 125 which is provided inan end position away from the movable table 123 on the machine base mainbody 121. The common base 124 has mounted thereon the cleaning unit 34and the wiping unit 35. The tank base 125 has mounted thereon a liquidsupply tank 126 for the function liquid supply and recovery apparatus 13which is described in detail hereinafter.

On a lower surface of the machine base main body 121 there are providedsix supporting legs 128 with adjusting bolts, as well as four casters129. On that side of the machine base main body 121 which lies on theliquid droplet ejection apparatus 10, there are provided a pair ofconnection brackets 130, 130 for connection to the supporting rack 21 ofthe liquid droplet ejection head 10. According to this arrangement, theliquid droplet ejection apparatus 10 and the auxiliary apparatus 11(common machine base 31) can be integrated, and the auxiliary apparatus11 can be separated and moved depending on necessity.

The small containing room 122 b of the machine base main body 121contains therein the main portions of the air supply apparatus 14 andthe vacuum suction apparatus 15, and the large containing room 122 acontains therein the tanks, or the like, of the function liquid supplyand recovery apparatus 13. The coupling groups 131 for connection tothese tank groups face the rectangular opening 121 a which is formed inthe upper surface of the end portion of the machine base main body 121(see left end in FIG. 42). A waste liquid pump 152 (to be described indetail hereinafter) is provided in a position near the rectangularopening 121 a.

The movable table 123 extends along the longitudinal direction of themachine base main body 121 and is made up of: a rectangular table 133which supports the common base 124; a pair of movable sliders 134, 134which slidably support the rectangular table 133; a ball screw 135 whichis disposed between the pair of the movable sliders 134, 134; and amoving motor 136 for rotating the ball screw 135 in one direction and inthe opposite direction of rotation. The moving motor 136 is connected toan end of the ball screw 135 through a coupling 137, and the rectangulartable 133 is engaged with the ball screw 135 in a screwed manner througha female spool 138. According to this arrangement, when the moving motor136 is rotated in one direction and in the opposite direction ofrotation, the rectangular table 133 and the common base 124 move backand forth in the X-axis direction through the ball screw 135.

The moving table 123 moves the cleaning unit 34 and the wiping unit 35which are disposed on the common base 124. When the moving table 123 isdriven, the head unit 26 is in a position right above the cleaning unit34 by means of the Y-axis table 24. Once the cleaning unit 34 has suckedthe function liquid in close contact with the plurality of functionliquid droplet ejection heads 7 of the head unit 26, the nozzle formingsurface 67 of each of the function liquid droplet ejection heads 7 getscontaminated or stained. Therefore, the wiping unit 35 comes close tothe plurality of function liquid droplet ejection heads 7 by means ofthe moving table 123 and operates to wipe out the contamination on thenozzle forming surface 67 (details of this operation will be describedhereinafter).

On a side of the moving table 123 there is disposed a flexible cablebundler 139. This flexible cable bundler 139 is fixed to the uppersurface of the common machine base 31 and the front end thereof is fixedto the common base 124; it contains therein the cables, air pipes,cleaning pipes, pipes for the waste liquid (to be reused), or the like(not illustrated; cleaning is described in detail hereinafter).

With reference to FIGS. 43 through 46, a description will now be madeabout the function liquid supply and recovery apparatus 13. As shown inthe piping diagram in FIG. 43, the function liquid supply and recoveryapparatus 13 is made up of: a function liquid supply system 141 whichsupplies each of the function liquid droplet ejection heads 7 of thehead unit 26 with the function liquid; a function liquid recovery system142 which recovers the function liquid that has been sucked by thecleaning unit 34; a cleaning liquid supply system 143 which supplies thesolvent of the function liquid for the purpose of cleaning; and a wasteliquid recovery system 144 which recovers the waste liquid of thefunction liquid from the flushing unit 33.

FIGS. 44 and 45 show the tank groups which are contained inside thelarge containing room 122 a in the common machine base 31. A pluralityof tank groups are mounted on a liquid-proof pan 146 of a drawer type.On the liquid-proof pan 146 there are laterally disposed, as seen fromthe left in the figure, a cleaning tank 147 for the cleaning liquidsupply system 143, a reusing tank 148 for the function liquid recoverysystem 142, and a pressurizing tank 149 for the function liquid supplysystem 141, which constitute the tank groups. A waste liquid tank 150,which is formed into a small size, for the waste liquid recovery system144 is disposed near the cleaning tank 147 and the reusing tank 148.

As shown in FIG. 43, the waste liquid tank 150 is connected to theflushing unit 33 through the waste liquid pump 152 and recovers back tothe waste tank 150 the function liquid ejected by each of the functionliquid droplet ejection heads 7 to the flushing unit 33. The reusingtank 148 is connected to the suction pump 153 of the cleaning unit 34and recovers the function liquid as sucked by the suction pump 153 fromeach of the function liquid droplet ejection heads 7. As shown in FIG.46, the waste liquid pump 152 and a gate valve 154 on an upstream sideof the liquid supply tank 126, which is described in detail hereinafter,are fixed to the supporting plate 155 and are mounted, as describedhereinabove, on the upper surface of the end portion of the machine basemain body 121 (see FIG. 16).

As shown in FIG. 43, the cleaning tank 147 is connected at its suctionside to the air supply apparatus 14 and is connected at its delivery ordischarge side to atomizing nozzles (to be described in detailhereinafter) 195 of the cleaning liquid atomizing head of the wipingunit 35. Namely, the cleaning tank 147 supplies the cleaning liquidinside thereof to the cleaning liquid atomizing head 195 under pressureby the compressed air to be introduced from the air supply apparatus 14.Although the details are described hereinafter, the cleaning liquidejected out of the cleaning liquid atomizing head 195 is impregnatedinto a wiping sheet 182 which is to wipe out the function liquid dropletejection heads 7.

The pressurizing tank 149 has connected thereto a pressurizing pipe 157which is communicated with the air supply apparatus 14. The deliveryside of the pressurizing tank 149 is connected to the liquid supply tank126 of the function liquid supply system 141. In other words, thepressurizing tank 149 is a main tank for the liquid material. The liquidmaterial inside the pressurizing tank 149 is send under pressure to theliquid supply tank 126 by the pressurized air to be introduced from theair supply apparatus 14.

FIGS. 47 through 49 show the liquid supply tank 126. The liquid supplytank 126 is fixed to the tank base 125 and is made up of: a rectangulartank main body 161 which is provided with a liquid level peep hole 162on each side and is closed by a flange; a liquid level detector 163which faces both the liquid level peep holes 162, 162 for detecting theliquid level of the function liquid; a pan 164 on which the tank mainbody 161 is placed; and a tank stand 165 which supports the tank mainbody 161 through the pan 164.

The tank stand 165 is made up of an attaching plate 167 and twosupporting column-like members 168, 168 which are vertically provided onthe attaching plate 167. It is thus so arranged that the height and thelevel of the tank main body 161 can be finely adjusted by the twosupporting column-like members 168. The (lid of the) upper surface ofthe tank main body 161 has connected thereto a supply pipe 169 which iscommunicated with the pressurizing tank 149. There are also provided sixconnectors 170 a for the pipes or passages (reference numeral 158 inFIG. 43) which are communicated with the head unit 26, and a connector170 b for opening to the open air (outside air).

The liquid level detector 163 is made up of a high-liquid level detector163 a and a low-liquid level detector 163 b which are disposed at aslight vertical distance from each other. The high-liquid level detector163 a and the low-liquid level detector 163 b are mounted so as to berespectively adjustable in height at the base portion relative to thetank stand 165. The high-liquid level detector 163 a and the low-liquidlevel detector 163 b have a pair of plate-shaped arms 163 c, 163 c whichextend toward the respective liquid level peep holes 162, 162 of thetank main body 161. The pair of the plate-shaped arms 163 c, 163 c haveon one end thereof a light emitting element 163 d which faces one of theliquid level peep holes 162 and on the other end thereof a lightreceiving element 163 e which faces the other of the liquid level peepholes 162. In other words, a transmission type of liquid level sensor isconstituted by the light emitting element 163 d and the light receivingelement 163 e.

On an upstream side of the supply pipe 169 which is connected to theliquid supply tank 126, there is interposed a gate valve 154 (see FIGS.43 and 46). The gate valve 154 is controlled to be opened and closed byan upper limit level detector 163 a and a lower limit level detector 163b and is adjusted so that the liquid level in the liquid supply tank 126always lies between the upper limit level and the lower limit level. Theliquid supply tank 126 is freed from the pressure on the side of thepressurizing tank 149 by the venting to the atmosphere. Therefore, theliquid material is supplied to the function liquid droplet ejectionheads 7 by a slight head pressure (e.g., 25 mm±0.5 mm) to be controlledby the adjustment in the above-described liquid level. According to thisarrangement, the liquid droplet can be ejected at a high accuracy by thepumping operation of the function liquid droplet ejection heads 7, i.e.,by the pumping drive of a piezoelectric element inside the pimp part 64.The running of the liquid from the ejection nozzles 68 of the functionliquid droplet ejection heads 7 can thus be prevented.

As shown in FIG. 43, six liquid supply passages 158 from the liquidsupply tank 126 are branched respectively into two, i.e., a total oftwelve, branch passages 158 b through respective T-shaped couplings 158a. Each of these branch passages 158 b is connected as theapparatus-side piping material to each of the twelve sockets 492 for thepiping joints 49 provided in the head unit 26. In addition, a gate valve166 is interposed in each of the branch passages 158 b. It is soarranged that the gate valves 166 can be temporarily closed as describedhereinafter at the liquid filling step.

A description will now be made about the maintenance apparatus 16, inthe order of the wiping unit 35, the cleaning unit 34, and the flushingunit 33.

As sown in FIGS. 50 through 55, the wiping unit 35 is made up of arolling unit 171 (see FIGS. 50 through 52) which is independentlyconstituted, and a wipe-out unit 172 (see FIGS. 53 through 55), both ofwhich are disposed on the common base 124 in an abutting positionalrelationship. The rolling unit 171 is disposed on this side of thecommon base 124 and the wipe-out unit 172 is disposed on the other(inner) side of the common base 124, i.e., on the side of the cleaningunit 34.

The wiping unit 35 of this embodiment has the following arrangement.Namely, while moving (traveling) a wiping sheet 182 (to be describedhereinafter) relative to the head unit 26 which is held stationary rightabove the cleaning unit 34, i.e., in the cleaning position, the wipingunit 35 is moved by the moving table 123 in the X-axis direction, tothereby wipe out the function liquid droplet ejection heads 7. For thispurpose, the wiping unit 35 is arranged to be rolled out of the rollingunit 171 to move around the wipe-out unit 172 for wiping operation andis rolled into the rolling unit 171.

As shown in FIGS. 50 through 52, the rolling unit 171 is made up of: aframe 174 of a cantilever type; an upper feeding reel 175 which isrotatably supported on the frame 174; and a takeup motor 177 whichrotates a takeup reel 176 for the purpose of taking up. The frame 174has a sub-frame 178 which is fixed to an upper side portion thereof.This sub-frame 178 has supported thereon a speed detecting roller 179and an intermediate roller 180 so as to be positioned on a front end ofthe feeding reel 175 in a manner supported on both sides. On a lowerside of these constituent parts, there is disposed a cleaning liquid pan181 for receiving therein the cleaning liquid.

The feeding reel 175 has inserted therethrough a wiping sheet 182 of arolled shape. The wiping sheet 182 rolled (or fed) out of the feedingreel 175 is fed to the wiping unit 172 through a speed detecting roller179 and an intermediate roller 180. Between the takeup reel 176 and thetakeup motor, there is extended a timing belt 183. The takeup reel takesup the wiping sheet 182 by the rotation of the takeup motor 177.

Though details are given hereinafter, the wiping unit 172 is alsoprovided with a motor (wiping motor 194) which feeds the wiping sheet182. The feeding reel 175 is rotated while being braked so as to actagainst the wiping motor 194. The speed detecting roller 179 is a griproller which is made up of an upper and a lower, i.e., two, freelyrotatable rollers 179 a, 179 b and controls the takeup motor 177 bymeans of a speed detector 185 which is provided thereon. In other words,the feeding reel 175 feeds out the wiping sheet 182 in a state of beingstretched, and the takeup reel 176 rolls up such that the wiping sheet182 does not slacken.

As shown in FIGS. 53 through 55, the wiping unit 172 is made up of: apair of left and right stands 191, 191; a base frame 192 which issubstantially U-shaped in cross section and is supported by the pair ofstands 191, 191; a wiping roller 193 which is rotatably supported by thebase frame 192 on both sides thereof; a wiping motor 194 which rotatesthe wiping roller 193; a cleaning liquid spaying head 195 which lies inparallel with the wiping roller 193; and a pair of double-acting type ofair cylinders 196, 196 which move the base frame 192 up and down.

The pair of stands 191, 191 are made up of stationary stands which arepositioned respectively outside, and movable stands 199 which areattached to the inside of the stationary stands 198 in a manner slidableup and down. At the base portion of each of the stationary stands 198,there are vertically disposed the above-described air cylinders 196. Aplunger 196 a of each of the air cylinders 196 is fixed to the movablestand 199. By means of the pair of air cylinders 196, 196 which aredriven at the same time, the base frame 192 and the wiping roller 193,the wiping motor 194, or the like, that are supported on the base frame192 are moved up and down.

The wiping roller 193 is constituted by a grip roller made up of adriving roller 202 which is coupled to the wiping motor 194 through atiming belt 201, and a driven roller 203 which comes into contact withthe driving roller 202 with the wiping sheet 182 sandwichedtherebetween. The driving roller 202 is constituted by a rubber rolleraround which is wound a rubber having resiliency or flexibility, e.g.,at the core portion. The wiping sheet to be wound therearound is urgedtoward the nozzle forming surface 67 of the function liquid dropletejection heads 7.

The cleaning liquid atomizing head 195 lies close to the wiping roller193 (driving roller 202) and sprays the wiping sheet 182, to be fed fromthe intermediate roller 180, with the cleaning liquid which isconstituted by a solvent, or the like, of the function liquid. For thispurpose, the front surface of the cleaning liquid atomizing head 195,i.e., the side of the wiping roller 193, is laterally provided with aplurality of atomizing nozzles 204 to suit the width of the wiping sheet182. The back surface of the cleaning liquid atomizing head 195 isprovided with a plurality of connectors 205 for connection of the pipeswhich are in communication with the cleaning tank 147.

The wiping sheet 182 which has been sprayed with the cleaning liquid isimpregnated with the cleaning liquid and is arranged to face thefunction liquid droplet ejection heads 7 to wipe them out. Below thewiping roller 193, a cleaning liquid pan is also provided in the baseframe 192 so that, together with the cleaning liquid pan 181 of therolling unit 171, the cleaning liquid to be dropping from the wipingsheet 182 is received therein.

With reference to the schematic diagram in FIG. 56, a brief descriptionwill now be made about a series of wiping operations. Once the cleaningof the head unit 26 has been finished, the moving table 123 is driven,and the wiping unit 35 is moved forward to thereby make it close enoughto the head unit 26. Once the wiping roller 193 has moved to theneighborhood of the function liquid droplet ejection heads 7, the movingtable 123 is stopped. The air cylinders 196, 196 are driven to moveupward the wiping roller 193 so as to urge or bring it into contact withthe function liquid droplet ejection heads 7.

Then, the takeup motor 177 and the wiping motor 194 are driven tothereby feed the wiping sheet 182 for wiping operation, and theatomizing of the cleaning liquid is started. At the same time, themoving table 123 is moved once again. While feeding the wiping sheet182, the wiping roller 193 is advanced so that the lower surface of theplurality of the function liquid droplet ejection heads 7 can be wiped.Once the wiping operation has been finished, the feeding of the wipingsheet 182 is stopped and the wiping roller 193 is lowered, and thewiping unit 35 is returned to the original position by the moving table123.

With reference to FIGS. 57 through 60, a description will now be madeabout the cleaning unit 34. The cleaning unit 34 is made up of: a capunit 211 in which twelve caps 212 corresponding to the twelve functionliquid droplet ejection heads 7 are disposed in a cap base 213; asupporting member 214 which supports the cap unit 211; and an elevatingmechanism 215 which moves up and down the cap unit 211 through thesupporting member 214.

As shown in FIG. 43, a suction passage (pipe) 216 which is communicatedwith the reusing tank 148 with a suction pump 153 interposed therein isbranched into twelve branch passages 216 b through a header pipe 216 aand each of these branch passages 216 b is connected to each of the caps212. Each of the branch passages 216 b is provided with a liquid sensor217, a pressure sensor 218, and a gate valve 219 as seen from the sideof the caps 212.

Twelve caps 212 are fixed to the cap base 213 in the same array and inthe same inclination as those of the twelve function liquid dropletejection heads 7. As shown in FIG. 61, each of the caps 212 is made upof a cap main body 220 and a cap holder 221. The cap main body 220 isheld by the cap holder 220 in a state of being urged upward by twosprings 222, 222 and is also slightly movable up and down. The cap base213 has formed therein twelve mounting openings 224 corresponding to thetwelve caps 212, and has formed therein twelve shallow grooves 225 in amanner to enclose the mounting openings 224. Each of the caps 212 isscrewed to the portions of the shallow grooves 225 in a state in whichthe lower part thereof is inserted into the mounting opening 224 and inwhich the cap holder 221 is set in position in the shallow groove 225(see FIG. 60).

On an upper surface of each of the cap main bodies 220, there is formeda recessed portion 220 a which encloses the two rows of nozzle arrays ofthe liquid droplet ejection heads 7. Around the perimeter of therecessed portion 220 a there is attached a sealing packing 227, and anabsorbent member 228 is laid down on the bottom part by means of a stayframe 228 a. On the bottom part of the recessed portion 220 there isformed a small hole 229. This small hole 229 is in communication with anL-shaped coupling 230 which is connected to each of the branch passages216 b. When the liquid material is sucked, the sealing packing 227 isurged against the nozzle forming surface 67 of the function liquiddroplet ejection heads 7 to thereby seal the nozzle forming surface 67in a manner to enclose the two rows of the ejection nozzle groups.

Each of the caps 212 is further provided with an open air vent valve 231which opens the recessed portion 220 a to the atmosphere on the bottomside thereof. The open air vent valve 231 is urged toward the upperclosing side by means of a spring 231 a. At the final stage of suctionoperation of the liquid, the open air vent valve 231 is pulled open,whereby the liquid material that has been impregnated into the absorbentmember 228 can be sucked. In the figure, reference numeral 231 b denotesan operating part of the open air vent valve 231.

The supporting member 214 is provided with a supporting member main body242 which has a supporting plate 241 for supporting the cap unit 211 onan upper end thereof, and a stand 243 which supports the supportingmember main body 242 in a manner movable up and down. To the lowersurface on longitudinal both sides of the supporting plate 241, thereare fixed a pair of air cylinders 244, 244. There is provided anoperating plate 245 which is moved up and down by the pair of aircylinders 244, 244. On the operating plate 245 there is mounted a hook245 a which is engaged with the operating part 231 b of the open airvent valve 231. In this manner, the open air vent valve 232 is opened orclosed by the pair of air cylinders 244, 244 through the operating plate245.

The lifting mechanism 215 is made up of a lower lifting cylinder 246which is vertically provided on the base part 243 a of the stand 243,and an upper lifting cylinder 247 which is vertically provided on theplate 248 to be moved up and down by the cylinder 246. The piston rod ofthe upper lifting cylinder 247 is connected to the supporting plate 241.The strokes of both the lifting cylinders 246, 247 are different fromeach other. As a result, by selecting one of the lifting cylinders 246,147, the lifting position of the cap unit 211 can be switched between arelatively high first position and a relatively low second position.

The cap unit 211 has the following arrangement to prevent the functionliquid droplet ejection heads 7 from coming into contact with the caps212 when the head unit 26 is moved to a cleaning position which facesright above the cap unit 211. The arrangement is that the cap unit 211is in a standby state at the lower end position which is set so as tokeep a clearance of several millimeters (mm) between the sealing packing227 of the caps 212 and the nozzle forming surface 67 of the functionliquid droplet ejection heads 7. As a result of upward movement to thefirst position, the sealing packing 227 of the caps 212 is caused to bein intimate contact with the nozzle forming surface 67 of the functionliquid droplet ejection heads 7. At the second position, a smallclearance (e.g., about 0.5 mm) is secured between the sealing packing227 of the caps 212 and the nozzle forming surface 67 of the functionliquid droplet ejection heads 7. In this embodiment, an arrangement ismade that the cap unit 211 is moved upward to the first position by thelower lifting cylinder 246 and to the second position by the upperlifting cylinder 247. It may, however, be so arranged that the upwardmovements to the first position and to the second position are carriedout by the cylinders that are opposite to the above-described ones.

The cleaning unit 34 thus constituted is moved by the moving table 123into a position in which it crosses the moving locus in the Y-axisdirection of the head unit 26. The head unit 26, on the other hand, ismoved by the Y-axis table 24 to a cleaning position which faces rightabove the cleaning unit 34 (cap unit 211). Then, by the operation of thelower lifting cylinder 246 of the lifting mechanism 215, the cap unit211 moves upward to the first position so that the twelve caps 212 areurged from the lower side toward the twelve function liquid dropletejection heads 7 of the head unit 26. In each of the caps 212 which hasbeen urged toward each of the function liquid droplet ejection heads 7,the cap main body 220 slightly sinks against the two own springs 222,222. As a result, the sealing packing 227 of the cap main body 220 isbrought into intimate contact with the nozzle forming surface 67 of thefunction liquid droplet ejection heads 7.

Subsequently, the suction pump 153 is driven and the gate valve 219which is interposed in each of the suction branch passages 216 b isopened to thereby suck the liquid material from all of the nozzles 68 ofeach of the function liquid droplet ejection heads 7 through each of thecaps 212. Then, the open air vent valve 231 is opened right before thecompletion of the suction operation, and the gate valve 219 isthereafter closed to complete the suction operation. Once the suctionoperation has been finished, the cap unit 211 is lowered to the lowerend position. During the suction operation, monitoring is made to seewhether the poor suction (or suction failure) has occurred or not toeach of the caps 212 based on a signal from the pressure sensor 218which is disposed in each of the suction branch passages 216 b. Duringthe safe keeping (or holding for stand by), or the like, of the headswhile the apparatus operation is stopped, the cap unit 211 is lifted tothe first position to thereby seal each of the caps 212 with each of thefunction liquid droplet ejection heads 7, whereby a safe keeping stateis secured.

First, with reference to FIGS. 62 and 63, a description will be madeabout the flushing unit 33. This flushing unit 33 is disposed on the box88 of the X-axis flexible cable bundler 87 (see FIG. 30). The flushingunit 33 is made up of: a slide base 251 which is fixed to the X-axisflexible cable bundler 87; a long plate-shaped slider 252 which isprovided in a retractable manner on the slide base 251; a pair offlushing boxes 253, 253 which are fixed to both end portions of theslider 252; and a pair of function liquid absorbing materials 254, 254which are laid out inside each of the flushing boxes 253.

The pair of the flushing boxes 253, 253 have widths corresponding toeach of the function liquid droplet ejection head groups 7 a of the headunit 26 and have lengths corresponding to the movable range in thedirection of sub-scanning of each of the function liquid dropletejection head groups 7 a, thereby being formed in an elongated shape.These pair of flushing boxes 253, 253 extend at right angles from theslider 252 to the upper side of the X-axis table 23 and are disposed ina manner to sandwich the suction table 81. At the central bottom surfaceof each of the flushing boxes 253, 253 there is attached a draincoupling 256 which constitutes a drain port. The drain pipe (notillustrated) which is connected to this drain coupling 256 is connectedto the waste liquid tank 150 through the X-axis flexible cable bundler87.

The slider 252 has fixed thereto a pair of mounting pieces 257, 257 ofthe X-axis table 23. The mounting pieces 257, 257 are positioned betweenthe pair of flushing boxes 253, 253 and extend toward the Θ-axis table82. The front end portions of these pair of mounting pieces 257, 257 arefixed to the base portion of the Θ-axis table 82. In other words, thepair of the flushing boxes 253, 253 are arranged to be movable togetherwith the Θ-axis table 82 through the slide base 251.

In the flushing unit 33 as constructed above, when the flushing unit 33moves forward together with the Θ-axis table 82 as shown in FIG. 30, theright side flushing box 253 as shown therein passes first under the headunit 26. At this time, the plurality of (twelve) function liquid dropletejection heads 7 carry out flushing operation in sequence, and the headunit 26 transfers to the ordinary liquid droplet ejection operation.Similarly, when the flushing unit 33 moves forward, the left sideflushing box 253 first passes right under the head. At this time, theplurality of function liquid droplet ejection heads 7 carry out flushingoperation, and the head unit 26 transfers to the ordinary liquid dropletejection operation. In this manner, the flushing operation isappropriately carried out while the head unit 26 moves back and forthfor the main scanning. Therefore, the head unit 26, or the like, doesnot move exclusively for the purpose of the flushing operation, and theflushing thus does not influence the tact time.

When the ejection of the droplet is suspended for a certain period oftime, e.g., when the substrate W is carried into, or taken out of, theejection apparatus 1, the flushing must be carried out. Therefore, whenthe ejection is held in abeyance for a certain period of time, the headunit 26 is moved to the cleaning position which faces right above thecap unit 211 to thereby carry out the flushing from each of the functionliquid droplet ejection heads 7 to each of the caps 212. In this case,when the cap unit 211 is present in the lower end position, part of theejected liquid from the function liquid droplet ejection heads 7 will bespread outside in a misty state through the clearance between thefunction liquid droplet ejection heads 7 and the caps 212. As asolution, the cap unit 211 is moved upward to the second position by theupper lifting cylinder 247, whereby the flushing is carried out in thisstate.

According to this arrangement, the clearance between the function liquiddroplet ejection heads 7 and the caps 21 becomes slight (or small),whereby the outward running or splashing of the liquid ejected from thefunction liquid droplet ejection heads 7 can be prevented. In this case,if the suction force from the suction pump 153 is kept to be operated onthe caps 212, the outward slashing of the ejected liquid can be moreeffectively prevented. It is considered to carry out the flushingoperation while the caps 212 are kept in close contact with the nozzleforming surface 67 of the function liquid droplet ejection heads 7.However, if the caps 212 are brought into intimate contact with thenozzle forming surface 67, the nozzle forming surface 67 gets stained.This idea is, however, not practical because it becomes necessary tocarry out the wiping of the nozzle forming surface 67 after the flushingwork.

When a new head unit 26 has been introduced into the ejection unit 1,the flow passages inside the heads of the function liquid dropletejection heads 7 are empty. Therefore, it is necessary, before startingthe ejection work of the liquid droplet, to fill the flow passagesinside the heads with the liquid material. In this case, since thesupply of the liquid material from the liquid supply tank 126 is carriedout only by the slight or small head pressure, suction becomes necessaryto fill the flow passages inside the heads with the liquid material.Therefore, in filling the liquid droplet, the following operations arecarried out. Namely, the head unit 26 is moved to the cleaning position.The cap unit 211 is lifted to the first position to thereby bring eachof the caps 212 into intimate contact with the nozzle forming surface 67of each of the function liquid droplet ejection heads 7. The liquidmaterial inside the liquid supply tank 126 is then caused to be filledinto the flow passage inside the head of each of the function liquiddroplet ejection heads 7 by means of that suction force from the suctionpump 153 which is operated through each of the caps 212. However, evenif the suction operation is carried out by the caps 212, the flow speedof the liquid in the flow passages inside the heads lowers and,consequently, the air bubbles cannot successfully be removed out of theflow passages inside the heads. This will cause poor ejection, orfailure in ejection, of the liquid droplet from the flow passages insidethe heads. Particularly, the air bubbles are likely to stay in thefilter 62 a which is disposed at the bottom of the connection needles 62of the function liquid droplet ejection heads 7.

As a solution, in this embodiment, the gate valve 166 is interposed ineach of the branch passages 158 b for liquid supply, and the liquidsensor 217 is disposed in each of the branch passages 216 b for suctionas described hereinabove. After starting the liquid filling (orcharging), the liquid material is sucked up to the caps 212 and, oncethis state has been detected by the liquid sensor 217, the gate valves166 are temporarily closed while continuing the suction by the caps 212.According to this operation, the pressure in the flow passages insidethe heads is reduced during the closing of the gate valves 166. With thesubsequent opening of the gate valves 166, the liquid material flowssuddenly so that the flow speed of the liquid material in the flowpassages inside the heads increases, with the result that the airbubbles are efficiently discharged out of the flow passages inside theheads. According to experiments, the flow speed of about 100 mm/sec.before closing the gate valves has sharply increased to 200–2000 mm/sec.when the gate valves 166 are opened after temporarily closing them.

The higher the rate of filling the liquid into the flow passages insidethe heads is before closing the gate valves 166, the more efficientlythe pressure inside the flow passages inside the heads can be reduced.When the liquid material has reached the liquid sensor 217, the flowpassages inside the heads are substantially completely filled with theliquid material. By using the liquid sensors 217, the timing of closingthe gate valves 166 can adequately be automatically controlled. Inaddition, by providing each of the branch passages 158 b, 216 b forliquid supply and for liquid suction, respectively, with the gate valve166 and the liquid sensor 217, the gate valves 166 can be separately orindependently closed at a suitable timing for each of the liquidfunction droplet ejection heads 7 even if fluctuations occur in theinitial ratio of liquid filling into the respective function liquiddroplet ejection heads 7.

The smaller the length of the flow passages between the gate valves 166and the function liquid droplet ejection heads 7, the higher theefficiency of pressure reduction after the valve closing, and thesmaller the amount of liquid consumption at the time of filling. Here,if the gate valves 166 are mounted on a portion which moves integrallywith the main carriage 25, there is no need of securing slacking for thepurpose of following the movement of the head unit 26 to be held on themain carriage 25, the slacking being provided in the passage portionbetween the gate valves 166 and the function liquid droplet ejectionheads 7. This shortens the length of the flow passages. Therefore, inthis embodiment, the gate valves 166 are mounted on the bridge plate 91which suspends the main carriage 25. Details are shown in FIGS. 64 and65. Twelve gate valves 166 are mounted, six each, on two stages of theupper stage and the lower stage on a stand 261 which is fixed to thebridge plate 91.

Six T-shaped couplings 158 a and six grounding couplings 158 c aredisposed on an upper plate 262 of the stand 261 which covers the placeof mounting the gate valves 166. Six liquid supply passages (tubes) 158which are in communication with the liquid supply tank 126 are connectedto the inwardly faced connecting ports of the T-shaped couplings 158 arespectively through the grounding couplings 158 c. Upstream portions158 b ₁ of these six branch passages 158 b which are connected to thedownwardly faced connecting ports of the T-shaped couplings 158 a areconnected to inlet ports 166 a of the upper-stage six gate valves 166.Upstream portions 158 b ₁ of the remaining six branch passages 158 bwhich are connected to the outwardly faced connecting ports of theT-shaped couplings 158 a are connected to inlet ports of the lower-stagesix gate valves 166.

Twelve pipe couplings 158 d are disposed on a lower plate 263 of thestand 261 through brackets 264. Intermediate portions 158 b ₂ of thetwelve branch passages 158 b which are connected to the discharge portsof the total of twelve upper-stage and lower-stage gate valves arerespectively connected to one end of the pipe couplings 158 d.Downstream portions 158 b ₃ of the branch passages 158 b which are theapparatus-side piping material to be connected to the sockets 492 of thepiping joint 49 in the head unit 26 are connected to the other end ofthe piping joints 158 d. The stand 261 is provided with a manifold 265for supplying the head unit 26 with the liquid without passing throughthe gate valve 166.

A description has so far been made about the apparatus for manufacturingan organic EL device. This invention can also be applied to the ejectionapparatus which is used for manufacturing other products such as colorfilters for the liquid crystal display device, or the like, to bemanufactured by a liquid droplet ejection method.

For example, in the method of manufacturing a color filter for a liquidcrystal display device, filter materials of red color (R), green color(G) and blue color (B) are introduced into a plurality of functionliquid droplet ejection heads 7, a plurality of function liquid dropletejection heads 7 are operated for the main scanning and subsidiaryscanning, and the filter materials are selectively ejected, to therebyform a multiplicity of filter elements on a substrate. In addition, anovercoat layer may be formed in a manner similar to the above in orderto coat the multiplicity of filter elements.

Similarly, the function liquid droplet ejection apparatus 10 of thisembodiment may also be applied to the method of manufacturing anelectron emission device, the method of manufacturing a PDP device, themethod of manufacturing an electrophoretic display device, or the like.

In the method of manufacturing an electron emission device, fluorescentmaterials of red color (R), green color (G) and blue color (B) areintroduced into a plurality of function liquid droplet ejection heads 7,a plurality of function liquid droplet ejection heads 7 are operated forthe main scanning and subsidiary scanning, and the fluorescent materialsare selectively ejected, to thereby form a multiplicity of fluorescentmembers on an electrode. The electron emission device is a generic termto include the idea of field emission display (FED) device.

In the method of manufacturing a PDP device, fluorescent materials ofred color (R), green color (G) and blue color (B) are introduced into aplurality of function liquid droplet ejection heads 7, a plurality offunction liquid droplet ejection heads 7 are operated for the mainscanning and subsidiary scanning, and the fluorescent materials areselectively ejected, to thereby form fluorescent members in amultiplicity of recessed portions on a substrate.

In the method of manufacturing an electrophoretic display device,materials for electrophoretic members of respective colors areintroduced into a plurality of function liquid droplet ejection heads 7,a plurality of function liquid droplet ejection heads 7 are operated forthe main scanning and subsidiary scanning, and the ink materials areselectively ejected, to thereby form electrophoretic members in amultiplicity of recessed portions on an electrode. The electrophoreticmembers which are made of electrically charged particles and pigmentsare preferably enclosed in microcapsules.

The function liquid droplet ejection apparatus 10 of this embodiment, onthe other hand, can be applied to the method of forming a spacer, themethod of forming a metallic wiring, the method of forming a lens, amethod of forming a resist and a method of forming a light diffusionmember, or the like.

In the method of forming a spacer, a multiplicity of particulate spacersare formed to constitute a minute cell gap between two substrates.Materials which are made by dispersing the particulate materials toconstitute the spacers in a liquid and are formulated into a liquidstate are introduced into a plurality of function liquid dropletejection heads 7, the function liquid droplet ejection heads 7 areoperated for main scanning and subsidiary scanning, and the particulatematerials are selectively ejected to thereby form spacers on at leastone of the substrates. This method is also useful in constituting cellgaps between two substrates in the above-described liquid crystaldisplay device and electrophoretic display device. It can also beapplied to the method of manufacturing a semiconductor which requiresthis kind of minute gaps.

In the method of forming metallic wiring, a liquid metallic material isintroduced into a plurality of function liquid droplet ejection heads 7,the plurality of function liquid droplet ejection heads 7 are operatedfor main scanning and subsidiary scanning, and the liquid metallicwiring material is selectively ejected onto the substrate. For example,this method can be applied, e.g., to the metallic wiring to connect adriver and each of the electrodes in the above-described liquid crystaldisplay device, and to the metallic wiring to connect thin filmtransistors (TFT) and each of the electrodes in the above-describedorganic EL device. It can also be applied to the art of manufacturingordinary semiconductors aside from this kind of flat display devices, orthe like.

In the method of forming a lens, a lens material is introduced into aplurality of function liquid droplet ejection head 7, the plurality offunction liquid droplet ejection heads 7 are operated for main scanningand subsidiary scanning, and the lens material is selectively ejected tothereby form a multiplicity of microlenses on a transparent substrate.For example, it can be applied as a device for beam focusing in theabove-described FED device. In addition, it can also be applicable tovarious kinds of optical devices.

In the method of forming a resist, a resist material is introduced intoa plurality of function liquid droplet ejection heads 7, the pluralityof function liquid droplet ejection heads 7 are operated for mainscanning and subsidiary scanning, and the resist material is selectivelyejected to thereby form a resist of an arbitrary shape on a substrate.For example, the method can be widely applied to the forming of banks inthe above-described various display devices, as well as to the coatingof photoresist in the photolithography which constitutes the main partof the semiconductor manufacturing art.

In the method of forming an light diffusion member, a multiplicity oflight diffusion members are formed on a substrate, in which a lightdiffusion material is introduced into a plurality of function liquiddroplet ejection heads 7, the plurality of function liquid dropletejection heads 7 are operated for main scanning and subsidiary scanning,and the light diffusion material is selectively ejected to thereby forma multiplicity of light diffusion members. This method is alsoapplicable to various kinds of optical devices.

As described hereinabove, according to the method of filling the liquidinto the function liquid droplet ejection head and the ejectionapparatus, the flow speed of the liquid at the time of filling (orcharging) the liquid into the function liquid droplet ejection head canbe increased. As a result, the air bubbles can be efficiently removedout of the fluid passage inside the function liquid droplet ejectionhead and the number of suction at the time of filling the liquid can beminimized. The work efficiency can thus be improved and the workabilitycan be improved.

On the other hand, according to the various kinds of manufacturingmethods according to this invention such as the method of manufacturingthe LCD device, the method of manufacturing the organic EL device, orthe like, the initial charging or filling of the function liquid intothe function liquid droplet ejection head can be quickly and smoothlycarried out, thereby improving the reliability of the manufacturingmethods.

1. A method of filling a liquid into a flow passage inside a functionliquid droplet ejection head having an ejection nozzle formed in anozzle forming surface of a head main body, comprising: bringing a capconnected to a suction pump into intimate contact with said nozzleforming surface; and filling a liquid of a liquid supply tank connectedto said function liquid ejection head into said flow passage inside saidfunction liquid droplet ejection head, wherein a liquid supply passagebetween said function liquid droplet ejection head and said liquidsupply tank is temporarily closed in a course of filling the liquid intosaid flow passage inside said function liquid droplet ejection headwhile maintaining suction by said cap, wherein the liquid inside saidliquid supply tank is sucked at least up to said cap, then said liquidsupply passage is closed.
 2. An ejection apparatus having: a carriagewhich moves relative to a workpiece; a function liquid droplet ejectionhead which is held by said carriage and which is provided with anejection nozzle formed in a nozzle forming surface of a head main body,said function liquid droplet ejection head ejecting droplets from saidejection nozzle to the workpiece while carrying out a relative movementbetween said carriage and the workpiece; a liquid supply tank which isconnected to said function liquid droplet ejection head; a cap unitwhich is disposed in a position away from the workpiece and which isprovided, in a position corresponding to said function liquid dropletejection head, with a cap which is connected to a suction pump and isbrought into intimate contact with the nozzle forming surface of saidfunction liquid droplet ejection head, in a state in which said carriageis moved to a position facing said cap unit, so that the liquid of saidliquid supply tank is filled into a flow passage inside said functionliquid droplet ejection head by a suction force to be operated uponthrough said cap, said apparatus comprising: a gate valve interposed insaid liquid supply passage between said function liquid droplet ejectionhead and said liquid supply tank, wherein said gate valve is temporarilyclosed in a course of filling the liquid into said flow passage insidesaid function liquid droplet ejection head while maintaining suction bysaid cap, wherein the liquid inside said liquid supply tank is sucked atleast up to said cap, then said liquid supply passage is closed.
 3. Theapparatus according to claim 2, further comprising a liquid sensorinterposed in a suction passage between said cap and said suction pump,wherein the temporary closing of said gate valve is carried out when,after starting the liquid filling into said flow passage inside saidfunction liquid droplet ejection head, the liquid has been detected bysaid liquid sensor.
 4. The apparatus according to claim 3, wherein saidcarriage further comprises a head unit which is made up of asub-carriage and a plurality of function liquid droplet ejection headsmounted on said sub-carriage, and wherein said cap is provided in aplurality of numbers to correspond to said plurality of function liquiddroplet ejection heads, wherein said gate valve is interposed in each ofbranch passages of said liquid supply passage, each of said branchpassages being connected by branching to each of said function liquiddroplet ejection heads, wherein said liquid sensor is provided in eachof said branch passages of said suction passages, each of said suctionpassages being connected to each of said caps, and wherein each of saidgate valves is closed when the liquid is detected by each of said liquidsensors.
 5. The apparatus according to claim 2, wherein said gate valveis mounted on a portion which moves integrally with said carriage.